Have name changed. Went to cambridge to do pre clinical medicine and then to clinical in london.
I applied over 14 years ago so things are very different (never heard of russell group?) but would suggest going for oxbridge if he will get the grades (predicted as well), and then putting another good uni eg bristol, edinburgh, then a couple of less popular ones.
Its true that some colleges are not as popular - at cambridge for example churchill, robinson, girton so may be easier to get into.
Things that will increase his chances of getting into oxbridge are - not just being academic - so being sporty or musical or into drama etc preferably at quite a high level. Also being able to think outside the box, laterally etc and generally coming across a bright spark, interested in life.
Oxbridge medical pre clinical degrees are definitely more academic and less clinical than other universities. The cambridge 2nd year exams are meant to be the hardest of any in the country. There are advantages and disadvantages of this more traditional clinical/pre clinical divide. It is perhaps hard to see where you are going in the first year - but you feel like a normal student and mix with non medics which i think is crucial. Also, to be honest you do most of your proper learning to be a doctor in house jobs, and on the job rather than at medical school and a good science base stands you in good stead, eg for postgraduate membership exams.
In your third year you get to do something diffent - it can be science but it can also be politics, sociology, theology - this is a fantastic opportunity and can really contribute to making a more rounded doctor.
Its also true that aren't enough places in oxbridge for clinical school and you have to reapply. however there are enough places everywhere - in my year most of the fun people went down to london and we all had a fantastic time. I felt we were leaving cambridge on a high after a really special time, and wouldn't want to stay longer. People from cambridge can go to oxford for clinical as well, and edinburgh as well as london.
if he really wants to go and has a chance then give it a go, its totally wonderful, but there's not point applying if hes not going to get predicted straight As.
hth