I did my undergrad at Aberdeen Uni from 2000 to 2004 and loved it. I think some of those above are exaggerating the downsides of the city.
I’m pretty obviously English from my accent and never had any issues from the locals apart from some gentle ribbing around 6 nations/world cup time. I think unless you go looking for trouble it’s fine. Also I never noticed rent or anything else being particularly expensive.
The campus based uni experience is great with a really nice community feel to it. I seem to remember hearing they also recently opened a fancy sports village/complex between the campus and beach so if your son’s sporty he should be catered to well.
I’ve also had experience of uni at Nottingham, Birmingham and Loughborough, and Aberdeen holds by far my fondest memories.