Bad smell.

I have the same experiences in the past. And unfortunately it's not only me who noticed it, my other classmates too, she's one of our classmates in school. However, we couldn't tell her that she has a foul breath, nobody dares to tell her. We're worried that maybe we'll embarassed her. So what I did, was talked to her in a distance as possibly as I can.

I think you should tell him it upfront but in a caring and nice way. Some people don't notice that they have really bad breathe unless someone tells them so. And some say that eating habits or the food you eat is the reason of having bad breathe. Certain food secretes a gas that gives that bad odor in our stomach. Usually most people that eat meat more often have the tendency to have bad breathe. There's no easy way to tell but to be honest in a way that your only concern is for his own good. Good luck and hope it turns out alright.

I always carry some breath mints in my purse and if someone has bad breathe I always offer them one.

I am sorry, but I really do not have a great sense of smell. I lost my sense of smell by working in a service station as a child pumping gas into cars. Now it does not bother me if someone else has bad breath.