Mom (88) accusing her loving children of stealing from her. Any recommendations?

My Mom is 88 years old and has always been such a giving,unconditional loving mom and has always been there for all of us kids.(we are still her kids but in our 60's))
In the last 2 years we all notice she is starting to accuse us of stealing her jewelry, and other things and really believes it no matter what we say. We find she has been hiding things in pockets, etc and when we find them she thinks we have placed them there to make her think she's going crazy. She's become obsessed with paying bills and has paperwork all over the place. She use to only want to be with her kids and grandkids and laugh and enjoy life. She can afford to have someone pay the bills, but instead she would rather be bogged down with paper work then with people and her family that loves her.
She goes in and out of these periods but it seems to be getting worse. She is pretty sharp and remembers people,names and recalls events and can hold a conversation. She had fallen a few times a few years ago and hit her head. I don't know if something could have happened but she won't go in to be checked. I live out of town and my sisters and brother live near by her so they are getting the brunt of it. I feel so bad and don't know what to do for my Mom. Is there help out there or a natural remedy or medication. It's been getting harder and she believes her version that we are the culprits. It's so sad for us watching her become someone else in this area. She has a husband 92 that loves her, they still travel and have a home in Palm Springs and San Diego. Any recommendations in those area if we can get her to go and seek some help. Mark