Personally I would write my brother a letter telling him you want no more to do with him.

Then my sister.

Then to my son I would say.... "I choose not to talk to them its my life and I will do as I please, its your choice if you listen to the lies told you about me by them just as its my choice to love you no matter what you decide to do.

I would then refuse to discuss with my son the people you have CHOSEN to have no more to do with.

Then let the cards fall where they will.

Remember not to discuss with anyone your reasons if you dont want to. You owe them nothing.