This can't be considered a real bl story. Neither of the two male protagonists are gay. They call each other brothers, but they quietly develop a feeling of "more than friends, not enough lovers".
They suppressed their emotions for various reasons, and tried to get closer to each other but went further and further away.
In the end, they both buried their tacit secrets deep in their hearts and bid farewell to this relationship with a kiss, as a beautiful and green memory...