You're not going to be able to get him to care about your health. If anything, it sounds like he may enjoy the back and forth you have with him over it.

Those needs should be taken care of and you shouldn't have to justify them. What would happen if you just took care of your medical needs without saying anything much to him? Do you need to ask him for something generally? A ride? Money? Ugh, you shouldn't have to ask for money or a credit card for necessities, especially not health stuff.