How do you respond to the relatives who don't support you / your aging parent?

Without going into details, my mom became a widow 24 years ago and was left with no money and no house. She has four younger siblings and all these years not only they didn't help, they even took the little things their parents left. They all support each other financially, emotionally, and physically but barely even call my mom. And of course this also means everything was left on my shoulders.

Once every few years they show up at my door, usually just to not pay for a hotel and I just don't know how to respond to them. Especially considering my mom lives with me and if I told them to f off, that would also mean she couldn't see them and she's already all alone except for me.

What do you do if you're in a similar situation? Do you call them out? Do you act like nothing weird is going on in this picture?