Not enough information, nowhere near enough.
Has he any underlying medical conditions and what drugs is he taking? If he is taking tablets do they stick and he finds them difficult to swallow?
Can he drink water without spluttering.
Does he have earache or has his voice changed?
Does he smoke?
He takes atorvastatin. He often says food and drink has “gone down the wrong hole” and starts coughing. He also sneezes a lot. Don’t laugh!! It sounds like post nasal drip to me but is there anything that will clear it?
Mr U has been prescribed Beconase Spray, it does not seem to have had any effect, and like Mr Smurf getting him to a doctor is like talking to a brick wall.!
I don't believe there is anything reasonable one can do to force a partner to stop doing something. One may ask, or may suggest they need to seek help/advice. Seeing the pharmacist seems a good idea as one can't deny there is an issue to investigate.