A question from a friend

He bought a U class ticket on the web site for 345$ to muc
He has to do a dental operation 3 days before the flight and the DR gave
him a letter to confirm that it is not so wize to fly in his condition
Ly refuse to refund but agreed to hold the Ticket for a 120$

does my frind have a case because of medical problem to cancel the flight?

I understand that U class is very very low class so it gets all the restrictions

Any advice?

Thanks
liorM