hi smilinize...it's truly hard to know what mom's motives are...she's extremely active for her age...she still lives alone (except when Robin is under her nose)...comes and goes wherever she wants when she wants, is sharp as a tack, except for the normal forgetfullness at her age. Robin has tried to convince the rest of us that mom's getting senile...we think it's a ploy to get herself back under mom's roof...the other kids won't allow that to happen.
As an outsider I would react differently to this situation than the way my husband and his other sister do. My real mom was a paranoid scitzrophenic and often tried to pull one over my eyes to get what she wanted...a trip to the doctor usually for prescription drugs. I had to be touch with her and often had to treat her like a child. My MIL isn't that strong with Robin...she'll put up with only so much, but most of the time I think Robin more or less runs the show. I've often asked my husband why he and his sister don't confront Robin full force about what she's doing. Their response if that Robin knows she's mentally ill and has used that against them before when they tried to intervene...Robin called the police on her sister saying that her sister had gotten rough with her...I know Robin's sister (my SIL) and I know my SIL would never, ever do that and of course once she explained to the police Robin's problem, they backed off. I think they, too, are a little worried about what Robin might do...take it out on mom when they aren't there for coming to us with what's going on. I called once to an elderly abusive counselor and told her about the situation...she said unless mom is willing to speak up against Robin, there is nothing they can do.
It's frustrating knowing that Robin, mentally ill and a drug user, has so much power over my MIL. Makes me want to take my MIL by the shoulders, shake her and scream "WAKE UP". At least when I'm visiting, Robin steers clear and knows better than to open her mouth around me...she knows I will tell her off.