Does your husband's job do a Blueprint for Wellness which is a free blood test panel that the company pays for.
First, he should have general tests run like comprehensive metabolic panel, cbc, glucose tests, iron, and then he would need a cardio crp which would show if he has elevated levels of inflammation in his body.
The problem with reading your email is that it is hard for us to diagnose him without the proper medical training. I would hate to diagnose your husband and be wrong while he is steadily becoming ill which could end up disastrous if it's something undiagnosed that is progressing. I don't know your husband age, weight or medical history so diagnosing him is not probable from this end.
I wouldn't have gone to an ENT because it sounds like your husband's problem is more serious than that.