Perhaps you could try something like suggesting a doctor for him to go to, or offer some cough drops etc. to hint at the problem. He isn't doing it to irritate you, I am sure. If that doesn't help, do you have a boss that you could ask to be moved into another area? I feel sorry for the both of you in this siutation...maybe ear plugs would help? Just a thought!
Ugh..if he's 25 years older than you, he's old enough to know he has a problem. If moving your seat is not an option, I'd find a distraction for my own desk. Anything...a mini Zen garden...snow globe...music box....I guess an iPod is out of the question...? My DH has chronic sinus problems. He is forever coughing, sneezing and hacking. For the most part I've grown used to it, but I can see how it can make you gag. The only thing that helps is corticosteroids, which he can't take often or long term. Surgery is our last resort, right now we're going a holistic route.
I will suggest this to DH, thank you...altho we have tried other methods of nasal irrigation with saline before, his true problem is nasal polyps...the prednisone can shrink them, but its an awful med. to take. Hmmm...I'm thinking, I wonder if doing this while he's on the meds. and then continuing it can help keep those polyps from growing big again...? Thanks again for your suggestion!