Oda mae definitely should have kept that money
I realize he got killed for it, but he dragged this woman around the damned city doing his bidding, nearly getting her killed, and obviously had zero way to compensate her for the time. That would have been the perfect way to say thanks. Even worse, they give it to the Catholic church who doesn't need the money and probably just spent it on relocating pedo priest.
She should have told his ghost ass to fuck off and got her money.