Yes, I would be very careful, indeed. Be a distant friend, if friend at all. I think he fell for a con artist, one who sinks her/his teeth into someone, bleeds them dry (and then some) and then leaves for another victim. Your H is only now realising how much he might've bled. Protect your S. Don't let him lend/give his dad anything. He has been a fool, wasted his own father's money that he probably worked his life for, so it would be awful if he gets money from his son. (And, I think this is all the vampire OW's doing.)
Me:57 H:52 M:28 Got another lawyer last year and filed. D35,S/D twins28,D22 EA4/04 End? Who knows? "Life is like a mirror. Smile at it and it smiles back at you." — Peace Pilgrim