ok. what happens if you raise the issue? he gets checked out or he chooses not to. If he gets checked out he either has it or he doesn't. if he has it, then there are limited things that they can do. but they can do something and caught early he has a better chance. if he doesn't, then no problem
otoh, if you say nothing, well, he either has it or he doesn't. if he doesn't then nothing. if he does, he may find out anyway and have the treatments or he may never find out and he'll die from it.
Your husband isn't a doctor. He can't diagnose this man. He may say something and look like an almighty fool. Or not. Who knows?
But what is the worst thing that could happen?
And, importantly, how could this man be harmed by raising the issue and how could he be harmed by not.
imo, it's all in how you say what you say.
Like autism (which I refer to because I know about it, not because I am tring to change the subject) there is a difference between saying to someone "Your child has autism" or even "I think your child has autism" and saying "X likes lining things up, doesn't he?" or "X isn't very keen on looking at you, do you know why at all?" or something along those lines. or even mentioning something you've read in a conversational way, and happening to list the symptoms in an isn't that interesting way and hoping they see something.