My elder mother has lived with my sister for several years and wants to remain there, my brother is trying to get guardianship, does mom have a choic

If your brother gets guardianship, the POA will be extinguished. Yes, as part of the process your brother will have to schedule a hearing and notify your mother of the hearing date, time, and location. You can call your county courts and check if there has been a hearing scheduled yet. Your mother may present her own choice for guardian, or resist guardianship entirely. Whether I can help you or not depends upon where you are in Colorado. I'm in Arapahoe county in the Metro area.