Mum's had a 'fall'

As some of you may know, my MIL had a leg amputated 6 months ago due to poor circulation. She also has dementia. Shes lives in her own home....her choise....she flatley refuses to consider going into a care facility/ home. She has a social services care plan in place and carers visit her 4 times a day to get her up, put her to bed and prepare her meals. Hubs visits her every day on his way home from work and we visit twice a day at weekends. She can not move herself at all. She cannot get herself into her wheelchair. The wheelchair is a manual chair but she doesn't have enough strength in her arms to use it. She was promised an electric chair, but 6 months on....theres no sign of it.
Hubs was on his way home from work today and the care agency called him....mum has had a fall....could he get there asap. They had called an ambulance about 4.30 pm.He was there within the hr. Mum had actually fallen off the Sara Stedy stand the carers use to move her around the house! She was lying on the floor with her foot stuck around the frame and a gash on her big toe. The young female carer didnt know what to say, just.. 'she fell off' but if its being used properly, that shouldnt really be possible. It looks like the carer had forgotten to put the break on, and its moved when it shouldnt have. 2 managers from the agency then arrived and the young woman was spoken too. Seems she has been suspended pending an enquiry. All this time, poor Mum is just lying on the floor. Hubs and his sister( who is here on a visit and had popped to the shop) have covered her and given her a pillow and shes drifting in and out of sleep.
Its been 4 hours now... still no sign of that ambulance....