Medicare appeal

My mom has been in rehab since back surgery for 3 weeks. She's had her time extended several times by Medicare. Her most recent appeal was denied so they are discharging her from rehab on Saturday. She's no where near ready, and everyone agrees.

The social worker said we can appeal the denial, but it can take up to 14 days and in the meantime we pay the per diem and therapy costs. Does anyone have experience winning a second appeal? Is there any rhyme or reason?