When Blaine discovers he likes playing football at recess Kurt gets upset, thinking its the beginning of the end for their friendship, but he ultimately bedazzles/glitters a football jersey for Blaine and cheers him on during games.
During one card exchange, which takes place in the school hallway, (elementary I think, they're still young, and not yet out) an older student bumps them roughly into each other and calls them a homophobic slur. Kurt asks his dad what it is and Burt does his best to explain it to Kurt, while trying to reinforce that whatever happens Kurt is fine and loved just how he is.
I think they ultimately end up dating, I think Kurt does lose his Mom, and possibly Blaine has to move away but I might be mixing that piece in from another story.
Thanks for any help!