While I am not giving you legal advice, I can give you some general thoughts. POAs can be financial, medical or general. What I would do is make sure the POA is current (meaning is it time limited), I would check the powers of the POA to see if it includes something similar to what he is wanting to do (some POAs will state one of the powers may be to collect or distribute personal property) and I would request a signed written note from her indicating her desire for him to pick up her stuff. I would want to have a copy of the POA and her note for my file.