Stakes are simply the consequences that will occur if a character fails at their goal. Failing to stop a shark before eating people, means that those people will be eaten.
Stakes have to be set up. Why is getting a date to prom so important? What negative consequence will happen if he fails? Why is it important to him? If you don’t know, I don’t the script will be able to convey it to a producer who’s reading it.
I suggest reading through the other loglines labelled under Drama and Comedy on this site. Read through the feedback and try to apply that to your own logline.
I just don’t follow the logic of why he must be a gay bestfriend in order to get a date. What’s the conflict? Who’s the antagonist?

Here’s an example using elements from you logline: When his homophobic parents confront him about being gay, a closeted nerd must convince a popular cheerleader to go?to prom with him so his parents won’t send him to conversion therapy. (32)

While i do identify antagonists and stakes in my example, it doesn’t present a concept that would take up a feature length movie.
The problem seems to be that the logline doesn’t present a clear, logical plot that is unique. The logline describes a concept that displays a stereotypical role, and it doesn’t describe conflict. Quite simply, what’s stopping him from getting a date just by asking someone? How does being outed at school directly connect to having to get a date for prom? ?How does acting like a gay best friend get him a date to prom?

For general information, review the Formula tab at the top of the page, and like I mentioned earlier, study other people’s posts and the feedback they receive. I know from experience that learning to review other loglines immensely helps with writing your own.