If you have power from the attorney, then I think you can withdraw the money, If the deceased person had other people depending on him like small children, it will be fair if you use the money on them first before considering yourself.
Power of attorney creates a fiduciary relationship. You are required by law to act in the best interest of the principle. Stealing his money for your own use is a criminal offense. The fact that he's dead doesn't give you the right to steal from his estate. In fact your POA ended when he died and you have no rights to do anything with his bank account now. Do not steal from this bank account, the consequences could be severe.