My question involves estate planning in the state of: California

My elderly mother created a Living Trust and granted a 50% share to her common-law husband, a 40% share to her son, a 10% share to her daughter-in-law. I believe the common-law-husband coerced her into creating the living trust.
Now my elderly mom can no longer remember the details of the Living Trust. I believe she is suffering from Dementia. Is the Living Trust still enforcible. Can I petition the court to be the guardian? Can I petition the court to nullify the Living Trust since she shows signs of Dementia?
Who has the right to decide the fate of my elderly mom, I the son or the common-law-husband? We want to care for my mom and have her live with us but she won't leave.
The common-law-husband has sent his grown daughter large amounts of my moms money, my mom does not know or is not capable of contesting these transactions.
My mom and the common-law-husband bought a home 15 years ago and took title as "joint tenats". The common-law-husband talked my mom into a "reverse mortgage", the common-law-husband has since sent most of the "reverse mortgage" funds to his daughter. My mom is not really aware enough to question him or look for receipts.
What options do I have when my mom won't or can't stop him?
One more problem is I live in Arizona and my mom lives in California.