family members coming empty handed

[pacrosby]

OP: It is NEVER too late to do the right thing!!!!

Perhaps, but if I'm understanding your point you and many others continue to make the mistake of thinking that there is only one right thing. And THAT is really the root of the problem, not the brother and not the mother. You are assuming that the brother has known for over almost two decades that the OP would like him to bring something and yet refuses to do the right thing. You are assuming the family members have known for almost two decades that the OP wants them to scrape the plates into the garbage (something I would NEVER want my guests, family or not, to do) and are refusing to do the right thing. And you may very well be wrong.

It's already been made clear on this thread that there is not one singular way of doing things. That not everyone has the same expectations. If you haven't asked, if you haven't made your expectations clear, you really have no reason to complain. And choosing to do so really says more about you than your guests.