She would have to provide an accounting for how this money is being spent. It's very suspicious she is taking the SS check money and the pension money out of your and your husband's joint account and putting it in a separate account presumably under her name and you and you husband can't access it to pay your household bills and common expenses like for ordering grocery delivery to your house.

I would report it and let a fraud investigator do forensic accounting of what she is actually doing with the money.

I would question how she was able to get POA in the first place behind your and your husband's backs. There's something fishy there. Did she lie and tell the judge both you and your husband aren't of sound mind?