is it usual for a hospital to decide not to rehabilitate after hip surgery?

My mother is 82. She has dementia and osteoporosis. I have been her Primary Carer since her diagnosis in 2010. We live in Scotland, UK.

A while ago she fell at home and fractured left hip. The hip was successfully pinned. The surgeon said she should bear weight as she could tolerate, and recommended immediate physiotherapy. After 7 weeks of trying (19 'points of contact') the physiotherapists told me they could not get her to walk and they were terminating therapy. I had offered my help early on, but it was refused. The therapist (and also a dementia nurse) told me she would probably walk again one day, spontaneously, it was only her dementia (fear of falling again) which held her back. About 2 weeks later, on 25 February 2014, I responded to her request to leave the rehabilitation ward by encouraging her to get up and walk out herself. She did so, with my help, her confidence increasing with each step. We got about 6m before nurses crowded round, expressing alarm, and encouraged her to get into a wheelchair. My request for therapy to be resumed was refused. I requested a Discharge Planning Meeting, at which I was told that it had been decided (without my input as Welfare Guardian) that her mobility was unlikely to improve, further attempts to improve her mobility should not be made, and for her own safety she should not be rehabilitated but should remain in hospital or nursing home.

Is it common for a hospital to make such a decision? It seems totally illogical to me, after an expensive operation and 7 weeks of therapy, to then do a U-turn and force her to live as a cripple simply to avoid the possibility that she might fall and become one. Is there any professional guidance for doctors about making such decisions? I appreciate it may not be effective in the UK or Scotland.