I don't think he is afraid to come out to his friends, but probably to his family. He had a reaction when LiHuan said he came out to his and they were fine with it. Maybe HuanWen's family is very vocal about their dislike of homosexuality, and Huanwen was jealous that Lihuan had it so easy.
It seemed like he was hiding something about himself from everyone including YuYang in the past few chapters. He says vague self-depreciating things in a quiet voice, admiring "pure/innocent" people's ability to cheer up from hearing simple wir6of encouragement and LiHuan's honest, persistent and headstrong personality. Like, what's wrong, Huan Wen? What's eating you?
That is true. He does have a mystery about him that I hope the author explores.
I wonder what Huan wen's hiding? Cuz it's kinda weird for him to be in denial or scared of coming out as gay (if he does happen to be gay) when his best friend is gay, his circle of friends are queers (i think) and just, generally people around him are open minded that it should be easier for a person to come out in his current situation. It looks like he's been hiding about for a very very long time that literally no one knows about it.