Man with fertility issues

Stephanie
Hey everyone. I'm recently engaged. I have a nine year old step son that biologically doesn't belong to S/O (LONG story... ex a cheater that's the basics) he was married for ten years and never conceived... he won't go get checked out because he's afraid of finding out he can never be a father biologically. 
So the question here... what do y'all know about male fertility treatments? Causes of infertility? What can I do to help him accept himself either way?