AIBU to ask for guidance around DC and A levels with university in mind - I'm clueless

History and economics seem a good mix

biology would then be the one with less time consuming activities like essay writing

drama - best I think as a hobby if you can afford that sort of thing - amateur dramatics

That wasn't the case for me personally.
I worked my absolute TAIL off to get a B at GCSE Maths - and that was with my very mathsy mum acting as my private tutor!
I went on to do Psychology as a degree, and although the stats was challenging, there were loads of good books to look to for help and computer programs that'll do the bulk of the work for you. And this was 20 years ago now!

I'd personally advise a mix, particularly if he isn't sure/set on any particular career.
For AS Levels, I picked;
Psychology - genuinely fascinated by the subject, found it came quite naturally.
English - Naturally good at it. Came easily.
Biology - Parents "encouraged" me to "do a science", I liked it, but it was by far my hardest subject.
Business Studies - Thought I'd should pick something "career-y" that would cover a broad spectrum of things. It looked quite easy, and actually, it was.

For A Level, I'd planned to do Psychology, Biology and English, but I HATED the teachers we had for AS English, so dropped that and continued with Business Studies for the full A Level instead.

I went to a very academic all-girls grammar school sixth form. There were very few "arts" or practical subjects being offered. Literally the only ones were Art or Music.

Maths A level is considered helpful for a psychology degree, because of the statistical part

They don’t really, a good grade at GCSE maths will be fine, same for biology. They will contain some maths such as statistics but definitely don’t require maths A level (I have a PhD in cell biology and no maths A level)

You said he enjoyed drama. But if he doesn't love reading and fiction I'd avoid a drama a level with analysis of various plays

Yes psychology needs a certain level of maths ability. It's often taken IME with maths A level but for sure that's not essential. You do need a decent maths knowledge and facility though.

What subjects is he looking at @Tomorrowtodaynever? You say he is undecided but in fact there are a number of subjects he has said no to, which leaves I guess science and maths, drama and other creatives (does he do art or music or DT?) and untried subjects such as psych, sociology, phil and ethics, politics (these are often untried before A level anyway).

Which way is he leaning?

Psychology definitely has maths. Not overly challenging maths but you need to be able to analyse data and they carry out statistical tests. As others have said psychology and Geography bridge the sciences and humanities so useful subjects and they go well with nearly all other subjects.
plus if you take essay subjects, they keep your maths up and if you go science route, they develop your essay skills.

lastly, in year 11 he will get the opportunity to go to open evenings and speak with staff and often current 6th form students about the courses. Then in the summer they often offer taster days. Even if they put down certain subjects they can change their mind after they get their results. So lots of time to make a decision.

Psychology requires a good level of maths because statistical analysis of experiments and investigations is a key part of the course.

Geography also makes use of statistics.

Both subjects are known for requiring -and developing - both literacy and numeracy skills. They both cover subject matter which is traditionally seen as a humanity and subject matter which is seen as a science. They both use scientific method as part of investigations.

I would suggest, unless he is aiming for a specific high-flying uni subject, it's probably best to pick the subjects he most enjoys.

Any consideration of what subjects price what to universities doesn't consider that he has to spend two years immersed in the subject and he's unlikely to remain motivated if he doesn't love it.

Education is primarily about expanding your mind rather than getting into uni. If he suddenly discovered a passion for a uni subject that requires a certain a level he'll be able to go back and study it then.

Psychology and Geography are both subjects that cover science and humanities, requiring significant maths beyond GCSE level but also proper essay writing skills.

Excellent subjects for the broadly uncommited.

I did a politics degree - my a levels were English Politics History - if he isn't keen on reading I would feel that rules a lot of subjects out!

Facilitating subjects are not considered any more.

That said, Cambridge does have a list of recommended subjects for specific degrees (or categories of degree) so if that's possible it's worth a look.

Otherwise for sure there are subjects that are needed for some degrees. And if he is interested in those degrees then he should consider those subjects. But taking two old-school fac subjs in and of itself will not open up all degrees. I mean obviously.

So some examples of degrees and subjects you need

Engineering - take maths and physics
Science (inc psychology) - take the science you like and one other (but this can include the trad sciences, psych, geography, env science, even PE). (Not true btw that most science degrees require chemistry A level. DS2 has just graduated with a masters in bio sciences and no chemistry beyond GCSE.)
MFL - take the MFL
Eng lit - take eng lit
Medicine/vetmed/dentisry - take bio and chem ideally
CS - take maths
Economics - take maths and econ is a good idea too but not required
Maths - take maths and FM

But degrees like history (in a lot of unis anyway inc eg Leeds and Brum IIRC) geography, sociology, class civ, philosophy, criminology, social policy and many others need no specific A levels as a rule.

I see he has no idea – he must have a leaning towards some subjects? They would be an indicator of a good direction (eg no way DD would want to take biology A level so med/science was off the table - all good). Agree with others it might be an idea to talk to a careers adviser. And yy subjects he enjoys and will get a good grade in are a good idea.

I see from your update @Tomorrowtodaynever he says no to geog, MFL and English. That's all fine. And it gives an idea of direction. A combo like biology, chemistry and sociology or psychology would offer a lot of degree options - med/vetmet/dentistry/biology/chemistry/biosciences/psychology. Swap maths for the psych and you could also do chem engineering and economics.

Btw re English – it's not (at all) about creative writing (not eng lit anyway) and it is very much about reading books. DD in her eng degree had to read a book a week for each of three modules every term.

Apols for essay haha

What are his favourite subjects and which is he getting best grades in?
Start from there

Usually universities prefer a higher grade in a “less favourable” subject than the other way around.
Most courses have no specific requirements but he should think about what kind of degree he might like and which A levels are sensible- for example chemistry is needed for medicine, maths & physics are best for engineering, science degrees often require at least 2 science A levels (geography and psychology are usually considered science subjects).

From what you have said Biology, psychology and sociology would be good ones for him to consider. Lots of different degree options there.
Economics will require maths

Russell Group is a very old fashioned way of looking at uni. Maybe for PhD level studies, research focused academics, or the oldy worldy subjects (art history or classics) they're a priority but for a kid doing psychology or some of the more modern subjects, they need to look at the best universities for their degree without restrictions. Some of the post 92s are much quicker, slicker and more impressive from a T&L point of view. Russell Group unis occasionally overlook teaching in favour of research although a layperson wouldn't see that.

There are university ranking lists which you can filter by subject, that's the best way to look at it. Look at the rankings, TEF etc. But all of this is down the line. He needs to sort out his A-Levels first. You're looking too far ahead.

Law A level and a law degree are quite different and having a law A level absolutely is not a requirement for a law degree.

I would also say that Law is one of the degrees young people sometimes get encouraged to do because it is a traditional serious degree. If you are interested in Law it’s a great degree but if you are not then it is a bit grim. Anyone who has studied Law at undergrad could probably name a couple of people who were doing law because their parents thought it was a good degree to have. I say this as a lawyer - don’t do a law degree unless you are really interested - you can still become a lawyer via a conversion course (GDL) after uni.

I'd say that although there are lots of new and exciting subjects it's probably not a good idea to do only new subjects because they are a bit of an unknown and you don't know how much you'll enjoy them.

If he has an idea about degree area he should look up required A levels. Some subjects are fussier than others, e.g. medicine needs chemistry and biology, engineering needs maths and physics, architecture needs maths, physics and an art subject. But even for those professions there are exceptions that have more relaxed requirements. All science degrees require two sciences but what they are will vary (and psychology, geography, PE can count as sciences), humanities have less strict requirements and only require one humanity. So two sciences and a humanity will open up the most doors if he's unsure. If two sciences fill him with horror then you're looking at a humanity degree and doing what he loves will be fine. But be aware that he will encounter far fewer locked in students studying humanities or social sciences than he will doing a hard science.

This often changes across year 11 and for many a level subjects there will be a minimum gcse grade so what he can actually do will depend on his results.

if he’s got some very clear definitely not he’s in a better position than most.