Can I use a Durable Power of Attorney to prosecute siblings who stole from Mother who has dementia? Should I?

My Mother just signed a durable power of attorney over to me. She has early Alzheimer’s and is getting progressively worse. My younger siblings, all adults, have been taking advantage of her dementia and every month like clock work when she gets her Social Security Check , come in and convince her to “loan” them money-which they never repay. I just found out that two of them have been forging her signature on checks. My Mother is poor and receives less than $1,000 a month to live off of, as they have squandered all of her life savings. Now, I find out that this past month, my sib took over $500.00 of Mom’s money this way and the month before took $500.00. This caused my Mother to overdraw at the bank and get into all kinds of financial messes. Can I use the POA to prosecute them, even though the money is long gone toward drugs and booze. Even if stop them from taking her money, they will steal her things and pawn them. I don’t have the room or money to bring her to live with me. And if I prosecute, they will be vindictive and retaliate. They don’t know I have a POA now, and will absolutely have a fit when they find out. They may even convince her to revoke it. I want nothing more from my Mother than to see her be able to live in her home as long as she can, and make ends meet, which she can without them. I don’t want any money or possessions from her and have nothing to gain financially from doing this. Restraining orders would mean nothing to them. What should I do????