Brother,

It's admirable that you want to help. These are complex dynamics and issues, it seems.

I think a psychiatrist is the best place to start. You'd need a whole team of various specialists to make a "house call" - I don't see that happening.

Clearly, Mom and Sister are ill. That could be mental illness, physical illness, or both.

We can't diagnose here but we are here to support you. A psychiatrist can evaluate and refer out to other medical specialists, as needed. Psychiatrists can recommend therapists. I think that could serve as an excellent adjunct to their treatment plan. You may learn you cannot solve their problems. Regardless, I hope it goes well for you and your family.

Take care of you, too. This is stressful and your health is important.