Maybe the guy started flying late - we know very little about his background! So what if he's 42 with 'only' 2400 hours! Better than 42 with 200 hours!!
I've met a lot of people like him with reasonable commercial experience but who are stuck on outdated types (Shorts 360 or Jetstream 31 for example) and see no alternative to career progression other than getting themselves a more modern jet type. Buying a type rating is definitely not something that started a few years ago - a mate of mine who is now a TRI got himself a 737 rating in 1995 having been stuck on Kingairs and old Citations for too many years.
Of course it is a risk and it may all blow up in his face but it his life and his risk to take!!
On balance I'd go for the Airbus!
Good luck!!