I remember reading a story a couple months ago where Gabriel was in a band with his brothers (including Castiel, Michael, Lucifer, & Balthazar). Sam was friends with Gabriel's cousin (Anna?) and she took him to one of their shows because she knew he was a fan. Sam and Gabriel start dating. I know Gabriel's mother could not attend the shows because she was deaf and could not hear their music.

I'm pretty sure Sam was living with Dean and ended up as a published writer at the end (although I could be mixing this up with another story)

Thank you Casey679!!