What to do after my mother (78) has given all her money to one of her grandchildren and has nothing left to live on?

I will try to keep this short but it is a crazy situation that began many years ago and has only gotten worse.

My niece, was raised by her fathers parents after a long custody battle. The grandparents that raised her are wealthy and she was given anything and everything she ever wanted. That is until she turned 17. At that point she asked my mother if she could move in with her. That's when 2 of my sisters and I noticed things were not normal. The kid was lazy, selfish, mean to mom, had issues in school and dropped out. Mom refused to believe that she was anything less than perfect.

This went on for a couple of years but nobody knew Mom was financially supporting her. Mom always told people her other grandparents were paying for things but the bank statements showed otherwise. Turns out, within about a year mom financed 3 vehicles for her grandchild and eventually one of the cars was repossessed by the bank because my niece never made a single payment. Mom was the co-signer and ended up having to pay almost $10,000 after the bank sent it to auction.

She also paid for multiple vacations in the two year period including several of my nieces friends. Mom denied giving her anything and would get angry when anyone tried to talk to her about it. Between checks, debit card charges and credit card charges upwards of $50,000 was spent on this one grandchild. There is no way of knowing how much cash was given.

Mom had said at one time she was worried that my niece would commit suicide so didn't want to upset her. I feel my niece might have used that go get mom to feel sorry for her and gave her everything she asked for so she wouldn't hurt herself.

Most of her other grandchildren have stopped visiting her. Not because they feel entitled to any of the money but because she makes a point to tell them how great the other one is and how good and successful she is when it is clear she is not.

Mom is now broke and in danger of losing the home her and Dad built. 2 of my sisters and myself have all talked to Mom and we were all yelled at and accused of picking on a poor kid who has troubles. My nieces mother lost custody of her as a baby and has never attempted to be a mother so has been no help in the matter.

I know one of the three of us should take over as Mom's power of attorney but there are legal costs that we are not in a position to afford and the way we were all verbally attacked when bringing up the money she's given away, we are reluctant to force anything.

We help out where we can but it is getting stressful and there are hurt feeling and some level of anger because of the whole situation. My sisters help out with cleaning and yard work and so on. I help with home maintenance, yard work, vehicle maintenance and whatever else I can. The three of us are stressed and angry and feeling the affects of anxiety.

Now Mom has been reduced to applying for any and all assistance she can and is at risk of losing everything. She has already sold most of the land her and Dad had and all that is left is the house and a few acres of land. The money for the land that was sold too cheap is gone and there is nothing left.

Would my nieces behavior be possibly considered elder abuse? Mom did give her most of the money and allowed her to help herself (including some forged checks) but it was money she couldn't afford and done so out of guilt or pity.

Thanks in advance for any advise or guidance you can provide.