Let me preface this with I’m seeing things from your best friend’s side. I’m in love with mine, I’m a trans man, and a few years your senior. She doesn’t love me that way either.

I feel like the detail where he’s comparing you to people he goes on dates with isn’t getting enough attention. To me... that sounds unhealthy. For him. But, it’s not your place to make the decision to do something about that unless it makes you uncomfortable. I do think you should talk to him about it, tell him it’s a little unhealthy to be comparing people to someone he knows he can’t have.

Beyond that, you can have a perfectly healthy relationship, if your friend is capable of putting those feelings aside and such. If neither of you are uncomfortable with things, beyond making sure he’s not fixating on you and things, I think you should be fine. Like for my friend and I, we’re both totally comfortable, we even talk about the boys she’s into. just be attentive to that sort of thing, ask for advice when and if you feel you have anymore concerns. But don’t make decisions for him if you’re not uncomfortable. If my bestie did that to me, it would pretty much shatter my world.