JWs and money problems, like most "families" and money- a recipe for disaster.
I would go along with the advice to show your Dad as much love and kindness as you can. Try not to unleash any "A-P-O-S-T-A-T-E" stuff on him. JWs are programmed to let monetary loans to other JWs go. Even in a recession. If you talk apostate stuff, he may decide that the JWs are the better option and go back-you don't want that.
It is better to keep your options open and show him you are not an Evil Worldly and like most people he encounters--normal, loving, kind and will be there for him when he needs someone deperately to talk to who is not in the dubs and who he can trust. YOU.