Can someone take money out of an account using POA and put in his own name?

My father had money in an account and when he died I found out the account is gone. My brother, using his POA put all the money into an account in his own name only. He said he did it because my father was afraid I was stealing from him. Ludicrous, as I have no access to this money market account, but that is his excuse. The will says that we were supposed to split 50/50, but now the money is all in brother's name. Is there any recourse or can a Power of Attorney give him the right to just take the money?