It’s better to ignore the obvious until you get to know the person well enough to ask- usually by then it will have come up in conversation anyway. Hubby doesn’t even mind if strangers ask, as long as they don’t do it in a rude way. I have no problem with people being uncomfortable from not knowing how to act and neither does he- but there is no excuse to be rude as some people really are. Some people forget a person with a disability of any kind is a person first- just address the person not the disability.
Well, I must agree that unfortunately some people are jerks. Please express to your husband my respect and appreciation for his sacrifice.