Now that it is hard to get a high risk loan, what kinds of housing help is there to get into buying a home when there is an urgent medical need?

There is no "help" if one can not afford to buy they merely continue to rent a home that may already have proper layout for the medical need.

Buying is not more expensive than renting. It just requires a loan, which also opens doors and avenues for altering the house for the medical needs. Renting a house with them already in place is the more expensive option.