Maybe there's no way around it if he's accepting their money. But most kids do a thing here or there that their parents would rather they didn't and their parents continue supporting them. There's too much vagueness here. It's actually got my troll-o-meter beeping quietly. We don't know how reliant he is on his parents. Obviously they aren't footing the full cost of his education or he wouldn't be $5k in debt. If the parents are paying a significant portion of his costs they'd be stupid to stop now just because he runs more than three times a week.I'd have been very unhappy if one of my sons at the mid point of their college time decided to join a fraternity but I wouldn't have said we won't keep on footing the bill if you do, not after having already having spent half a fortune to get them that far. All the money spent so far goes down the drain for me (hypothetically) and for this guy's parents..
If he's not going to take my original advice and not tell them, I think he should call their bluff and tell them that if he can't run as he likes because they won't pay for his college he'll drop out and maybe get a job in a running shop. He doesn't necessarily need to follow through, though he might need to. But it's a counter move that should catch his folks off guard.