How can I make sure when my mom is sick my dad can't sign her out?

Turns out she had a UTI and an infection in two of her toes, spent 3 days in hospital. Before the hospital she wouldn't eat hardly anything and just slept in her chair and didn't want to go anywhere. But in the hospital she was doing good My dad took her home and now 2 days later she is right back at square one! In the recliner not eating and whenever we try to stand her up her legs are not working properly and she either falls getting the walker or if we're close enough to her recliner she will try to sit and ends up sliding out of it! She is a large woman and me, my brother and dad try to get her up. But sometimes she is not cooperating. And paramedics have to be called. She was going to be sent to physical therapy in the hospital but he brought her home. And I'm at my wits end trying to care for her.