My Mom's personality has changed drastically. What do we do?

This year she has begun swearing and ywllinf. Her anger is always directed towards my husband. He can't join a conversation that she doesn't roll her eyes and start arguing no matter what the subject. She had her storage unit emptied into our garage. It is so full of her boxes that it can not be used anymore but she won't go through her things claiming we want her to give them all up. My husband bought me a set of pans last christmas and she got furious because he didn't ask her first. He offered to open doors for her and she snaps off at him. She also threatens to call the police if he touches her boxes and a day later asks him to bring some inside. It is hurting my husband greatly. She gets mad if he joins a conversation but thinks nothing of listening to he and I talking and making comments from down the hall. I can't stand this anymore. She taught me to be polite to others and she can't even be civil anymore. What am I to do. She is trying to chase my husband away and I don't know what more he can do. Suggestions? Is this the onset of dementia? Her doctor has asked that I accompany her on all visits because she doesn't answer questions and forgets why she's there. She is still sweet to all others but my husband and he's the one that helps her whenever she needs it. He's the one that drives her to all appointments and shopping when she wants and then she cries that he doesn't like her. Any ideas.