tell him to be himself, i know he will have already heard that a million times, but its true i have a best friend whos gay and he has been through some tough patches but he stuck with it and never let anyone change him. he held his head high and eventually people kept their mouths shut. so tell him that he should be open about it. then people will know that he doesnt care what they think
You can tell him to be himself and do what makes him happy. Some people won't like that he is gay if they find out, but that just means he will be able to tell who will be a good friend easily. There is nothing wrong with him, just some people don't understand, and when people are confused they may act mean. Be confident and love yourself. Let him know you're there for him.