oh my goodness, your brother IS a prick. A self-righteous prick.
Credit card debts are unsecured. They can just stop paying them. Let them and your brother know that THEY are the ones "bringing reproach on Jehovah's congregation" because THEY are the ones who ran up debts they couldn't pay. I wouldn't give them two cents.
If they become homeless, they might have to come live with you! It would make it pretty hard for them to refuse to speak to you, eh? I'd offer them living space if necessary, food if necessary, but not a single dime.
I just love the crazy logic -- we need $10K, so hurry up and give it to us before you get DF and we can't talk to you any more. Jesus!