How does one go about getting diagnosed so that they can qualify for disability? So that they can afford insurance for medication?

My husband was fired a year ago (losing his medical insurance) for calling into work sick or being sick at work to often. He went to endless appointments with no one giving him a diagnosis which led to him being fired for "faking sick".

He pukes every morning for about a week and is then okay for a couple weeks before it happens again. He went to an urgent care where the nurse told him it was CVS but that she couldn't legally diagnose him at an urgent care.

It is impossible to keep a job when you may unexpectedly puke at any time and have to miss work for a week once it begins.

Let me know if a different topic room would be better suited for this question.

Update: we cannot go to any free clinics because my income is too high. He got a quote to see a Dr for this out of pocket and they said it would be over 7k.

He also has severe ADHD which according to the nurse is probably why he has CVS. Their brains process stress different or something like that.