Brother of Mrs has put up enough road blocks to be pretty obvious about not wanting dad to come, no matter what he's saying. He probably means well.

If Dad spends so much time with you, YOU are probably who he considers family and is comfortable around. Have you asked him what he wants to do? The environment at his son's home doesn't sound like a very pleasant one for him. I agree with those who say spend Christmas with him. Go on holiday at another time. Ask Brother of Mrs to come for Christmas if you're so inclined - just let him know how much the hotel/bed & breakfast will cost him.

Do what you can for him now, and you won't later wonder if you should have done more. The same is true for all of us and all our loved ones.