I wouldn't let them have it out of principle lol.....blatantly trying to do the guy over if they're that keen to have it (no garage does you favours), if it's a good solid car then definately worth getting repaired! However, might be a bit of hassle sourcing parts etc and i'm guessing he's without a car in the mean time? Nightmare when something major happens to your car like that and you're not mechanically minded, gonna cost you either way sadly