Being fat is not the worst thing you can be. There are an infinite number of things you could be that are so.much.worse than fat. For example: racist, sexist, bigoted, mean to people on the Internet, mean to babies, mean to cats, that person who takes up two parking spaces.
He's comfortable with his body, and you should be too.
We can all stand to make better choices for our health, no matter what size our bodies are. Sending the message that healthy has a certain look only leads to more discrimination.
"Your weight does not measure your worth."