Growing Up Lonely (Reader x Tadashi/Hiro)

Tadashi, Hiro, and (Y/N) were best friends. They grew up together, had parties together, and just generally loved each other's company. But one day, Hiro went up on that stage to audition for SFIT.

Everything changed that night. Tadashi died in the fire, Hiro locked himself up in his room, and (Y/N) was all alone.

But.... What if Tadashi never actually died?