Honestly, I would get him to seriously reconsider his options. If he isn't shining at A level he will struggle to shine at uni (speaking from experience, not trying to be hairsh). I got ABB in chemistry, biology & maths.
I didn't get the grades to apply for medicine so opted for biomedical sciences at a very good university which had the option to transfer to medicine after 1st year. I actually turned down a place on a biomedical course at a different (what I thought of as a "lesser") university who actually offered an accredited biomedical science degree and that is probably my biggest regret.
Of almost 400 students, only 1 managed to transfer to medicine after the first year (and you need to get a first to even be considered). At the end of the course, I'd say approx 20 have gone on to study dentistry/medicine but none of these via GEM. I did actually get a place to study medicine in Durham after graduating but I couldn't bear the thought of a further 5 years at uni (then however many years of training) and wanted to get in to work.
To get back to the point of accredited vs unaccredited, I left with a biomedical science degree specialising in pharmacology but unable to actually apply for a biomedical science role without undergoing another 18 months coursework to have my degree accredited. Had I taken the accredited course I would have had a lot more job opportunities as there are lots of biomedical scientists in every hospital lab. I'm very fortunate to have ended up with a very degree specific job but it's very niche and there are only 20 people across the UK who can do my job.
Would he consider pharmacy? That would be my advice to someone in his position (aside from nursing obviously). You even say he went through a spell of not wanting to go to university at all, and in the kindest way possible, that won't equal the drive required to sit through 8 years of university doing 2 degrees back to back.