Not settling a debt is very high on my list of sins. I understand that different people have differing attitudes to the issue, but my approach would be to pay him a visit to try to agree a payment plan (5k/month?). If he agreed and followed it, then fair enough - but I’d limit all future credit...
If he has just bought his wife a new car, are you sure he can’t pay you as opposed to won’t pay you? Either way, as he’s an associate, not a friend, personally I would cut the credit line.