ahhh its ok probably the best thing あなた can do for him is just be there try to make hime laugh または get him choclate. just let him know that your there and あなた care
I guess it all depends on what do あなた both feel for each other.If there's もっと見る than just friendship between the 2 of あなた even remotely possible,perhaps your gay friend would even shift to bisexuality.Who knows what might happen between 2 best friends?