What can you do with a rude family member ?

Is this rude like they think that person is faking it? Or are they talking about how to divide up their possessions after they die? Or is it something else? It's kind of difficult to ascertain the situation without further information.

What do you mean by "rude."?

If he's being rude to them, perhaps they're simply being rude back?
For example my dad was always a misery-guts, and even when he was dying of cancer he glared daggers at me.
I think one of the last things he said to my mother about me as he lay dying was "When's he going to get a bleeding job?"