My husband has horriable nasal congestion!?

He needs competents docs like those at a major med center.

Those docs failed him which is all the more worse bc he had mri's & cats.

Did they recommend a consult w/ allergist?

But before the allergist, an ENT, medical doc [MD], Ear Nose Throat, should do an endoscopic exam under local anesthetic to see if there are physical probs w/ the nasal area like badly deviated septum, blocked sinuses, chronically inflamed [swollen] tissue, like turbinates; infections, etc.

If so, probs like the septum, turbinates & blocked sinuses can be dealt w/ with minor surgery.

If he's getting dry mouth bc of mouth breathing, that can damage the enamal on his teeth.

Consider a humidifier for your residence and eliminating allegery-causing things like carpets, cats; put an air-tight cover on the mattress, get hypo allergenic blankets n pillows n shampoo n soaps.

Use ac to clean incoming air.

I have a similar problem. My nose is congested almost all the time. I have tried every product available over the counter, and I have tried several medications from my doctor. Nothing seems to make much difference. The only time my nose is EVER completely clear is when I use nasal spray like afrin or similar. People tell me that it is not good to use it so much. They say that when the spray wears off the congestion comes back even worse. This does seem to be true, but If I don't use it, I'm stopped up anyway so what's the difference, right? I had the problem before I started using the spray, so obviously that was not the actual cause of the problem. I wish I knew the answer to this, and I do sympathize with your husband. It is a miserable condition to never be able to breathe through your nose like you should.