Forcing a parent into assisted living. Any advice?

If they don't want to go, you cannot force them. On the other hand, if the DOCTOR says they are no longer safe at home or incompetent, he can help place the individual in a proper facility. This is where APS can be your friend, they come out and if the senior is living in poor conditions, or starving or disoriented, they help get them placed.

Apomay what others on this site have recommended is when the senior is admitted to the hospital, tell the discharge planner that they can't go back to where they were living. Then they'll work with you to help get them placed. That's assuming that they're not able to take care of themselves and have no support system that wants them to go back to where they were living.