How to revoke a POA?

I have the POA naming her husband as POA with me as secondary. Husband dumped her at a hospital last November, cut off all contact, cleaned out their accounts and sold her house (signing the sale documents as her POA). I don't have the money to fight him. I have contacted every agency under the sun in Palm Beach County. I just get a merry-go-round of referrals to other agencies (that I have already contacted). I'm older, with some health issues myself. I am so far away. I can't find anyone to help her. I'm frightened 😨 I can't believe he is getting away with this!

She doesn't qualify for Medicaid. She has money, we just don't know where it is! He has a woman in Canada "helping" him. I'm worried he's moved the money up there. I asked the ALF if they had someone who could help us get a claim filed for her long term care insurance (he won't file a claim, and the one I filed was denied, because I am not the "Primary"). The insurance would satisfy her monthly care. I've talked to three different, upper management, people there. They basically told me to go pound sand. Not their problem. Now they won't even respond to me. Except to send texts when she needs meds, pull ups, toiletries, clothes, a haircut, etc.