I am my dh's caregiver. I can manage everything except his shower. I think the solution would be a sliding tub transfer bench to get him in and out of the tub. A good one costs $300 or $400. I had a wonderful CNA until a couple of weeks ago when she had health problems and has to take some time off. So right now I'm using sudsing bath sponges to wash him but he really needs a shower at least once a week.
I seriously doubt the Medicare system will pay for such a specialized and expensive piece of equipment simply because it would bankrupt the system supplying such things, but then they supply VERY costly drugs, so who knows.
This is basically for you to research unless someone here happens to know the answer, and I hope that's the case. It's so difficult to figure out just who to call, and to get an answer when you DO find out. So I wish you best of luck.