It all depends on the amount. If the amount is large, then take a loan or ask for help from any fund that will specialize in this degree. There are many groups in VK where you can offer a record asking for help.
You can always ask for money. but this is also essentially work. You work with statistical data - that is, in fact, a certain small number of people will agree to help free of charge. And you will have to go all day and look for people everywhere trying to convince them to help you. Therefore, one must have tremendous willpower for the highest level of resilience.
There are federal and regional programs, depending on the disease. It is also possible to apply to various charitable foundations. Health to you!