What papers do we need to file to have someone from the court to oversee my mom’s affairs?

My mother has dementia and can no longer handle her finances or medical care. My sister is in charge of everything and is not letting my brother and myself anything that is going on. She will not tell us where my mother is, how she is, or anything about my mother’s finances. My sister has made the statement that she is going to draw out all of my mother’s money from the bank and that she has the right to do whatever she wants. The following are from my mother’s revocable trust and patient advocate. DESIGNATION OF PATIENT ADVOCATE FOR PERSONAL CARE, CUSTODY, AND MEDICAL TREATMENT 1. Patient Advocate, I designate my daughter (my sister’s name) as my agent and advocate with respect to my personal care, custody, and medical treatment. Should she be unable or unwilling to act as my agent and advocate, I designate my Sons, (my name, brother’s name) as my co-agents and advocates. REVOCABLE TRUST I (my mother’s name) on this day sign this Trust Agreement (“Agreement”) with (my mom’s name) and (my sister’s name) as trustees, both of whom, and the survivor of them, and any successor trustee, will be called “Trustee” in this Agreement and referred to in singular neuter pronouns. 4.1 SUCCESSOR TRUSTEE. When I am unable to serve as Trustee or as a co-Trustee (as determined and certified in writing by any remaining, or if none, the next successor, Trustee), or if I fail to select in writing a successor Trustee within 30 days after receipt of knowledge of the then sole Trustee’s resignation or refusal to act, the following, able and willing to act, shall become successor Trustee: First (my sister’s name), Second, (my name). At my death, both of those named above willing and able to act shall act as Co-Trustees. If only one named successor Trustee is able and willing to act, that successor may serve as sole successor Trustee.