Why not get in touch with the Jog Scotland groups - there are ones in both Tarbert and Lochgilphead. These tend to be predominantly women but there are men as well. There may be extra forms etc required as he is under 16, but it should be OK. Try emailing
jogscotland@argyll-bute.gov.uk for more info and advice on the local groups. At the very minimum this would give your son a structured training plan to follow, plus a bit of company for his training. There may even be other folk his age there.
Good Luck to you both with your training.