I live in California. My mom lives in Michigan. How can I help her from so far away?

You can monitor your mom's behavior from afar, but if the short-term memory loss is a symtom of a bigger problem, like dementia, then unfortunately, the problem may get worse. You're going to eventually need to bring in back-up locally. Is there a family member, friend or neighbor who can visit your mom and monitor her? Its a harsh reality to face, but its better to get a plan in place now and be prepared for the future. Plans, in the form of who is going to look after mom, as well as getting medical and legal docucments in place, is very important.
We have a section of the website for long-distance caregivers. I think it will provide you with some useful information. Here's the link:

https://www.agingcare.com/topics/35/long-distance-caregiving