[392cobra]

Scott,
I'm sorry you and your family are having to go through this with your Dad.

Your Dad has been acting irresponsibly for some time. There is no reason to believe he is going to start being rsponsible now with your credit at risk.
I would not co-sign,period. You will end up with damaged credit and paying the $75k yourself in the end. You would be better off just giving him the money.Then expect him to be back for more and having an enemy if you don't give more.

I would see that see has a roof over his head and food but nothing more than that.

Tough love time.