I became my Mother's POA in 2013. I only needed to use it April through August 2015 when she lived with me. During those 5 months she gave me all her assets (household stuff) and talked about it so much that all her home care workers were well aware that she did infact, give me everything. She decided she wanted to go live in a nursing home and on the day I signed her in, she had my POA revoked and gave it to a grandson who now wants to take all the things Mom gave me. Can he do that?