A cheaper alternative, if you have a straight run of stairs, is a stairlift. Grants are easily available in Scotland, not so easy in England. Follow Mara's advice for help in this regard. Speaking from experience, and looking at the future, the stairlift is the more valuable investment.
The problem with disability caused by a fracture is that it may not be considered a permanent problem that would qualify for a grant. You're not likely to get a grant based on what may or may not happen in the future with the PD.