Why does my elderly husband blow his nose at the dinner table and restaurant?

I think every elderly person I've ever known has blown their nose at the dinner table.

Look up gustatory rhinitis. I too have started getting a runny nose related to eating. He blows his nose because it's runny. If you want to see why his nose is runny, take him to an EN&T doctor to see if he's allergic to something now, or treatment.

I don't know if he has what I have. Whenever I eat anything -and it doesn't have to be spicy, I get runny nose. I don't have a cold or an allergy to the food. My nose just seems to get runny when I eat. My niece once saw me get up to blow my nose discreetly after we had lunch. She said that she was relieved to know that she's not the only one who has that problem. I never had this problem until these past recent years. Can't say old age because my niece is in her 30's.

Or maybe blowing his nose is like others with dementia who gathers napkins, hoards napkins, refuse to throw napkins. It's a new habit.

he has early stages of dementia and every time we are at the table either home or restaurant he picks up a napkin may it be paper or cloth and blows his nose. He doesn't have a cold or allergy.

Because it is running? It's congested? He has a cold?

Have you told him you would prefer that he leaves the table? What does he say?