He should have called about the bill(s) back in December when they first arrived. If he hasn't made any payment then he is just being irresponsible and needs to start paying.
I did not have insurance about 12 years ago when my appendix ruptured. I ended up in the hospital for 10 days. The doctors saved my life (without surgery I would have been dead) and over time I paid the $86,000 bill.