I think the only way to get a definitive answer would be to call each of the companies she is an AU on and ask them. As an assumption I would think each company would have their own policy on this. Even if it is similar therd may be differences that could affect her.
Another option is to talk to an elder financial advisor. I'm certain that they would be very useful in helping to be sure your mom is not left up the creek so to speak if you dad where to pass on first.
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