It would seem that your mother is the one to make a claim, if anyone. Does she say she was harmed in any way? From your post, I am not understanding what her concern is.
She could have decided not to sign any of the papers, right?
What I might be missing is that you believe your mother was incapacitated or unfit in some way to sign these three contracts.
More details are needed.
Actually, the Bank cannot deny the mortgage based on her age as it would be age discrimination. Of course, they would have been looking, in part, at the amount of equity in the property at the time the loan was given.
Mr. Brinkman is right. There are details missing with which to help you. For instance, were these loans "churned" by the same bank, not for the purpose of assisting you Mom, but for the purpose of generating fees. Or were the loans from three different banks.
If she is concerned that she was not treated fairly, your best recourse would be to sit down with an attorney who practices in the area and let them do a complete analysis of the situation.
This answer does not constitute legal advice and does not and is not intended to create an attorney-client relationship. The law may vary depending on the state in which you reside. It is intended only to give some direction in which to seek assistance.
Seek out an attorney that practices in mortgage foreclosure defense. I can not tell from your fact scenario, but you seem to be hinting that there was some sort of fraud perpetrated against your mother. If that is the case, there are three causes of action (claims) she might have against the bank, under a law called "RESPA" (real estate sales and procedures act), another law called "TILA" (truth in lending), and the consumer fraud and deceptive practices act. some of these common "defenses" to mortgage foreclosure actually are counter-claims which can get your mom damages ($) to offset her mortgage.
But,this is all speculation as to what MIGHT be possible with the right facts. I think this is the type of lawyer you need to sit down with to figure out if you have a case.