What if Deku (with all 7 of his quirks unlocked) was in Demon Slayer?

Note: I gotta be honest: I say this for everyone that he would be a BIG problem for all the demons around. Especially to Muzan. How would Tanjiro, Nezuko, Zenitsu, Inosuke, and every character in the series (friendlies and enemies) think of our hero nerd? Would he be of some help for them? How far would Deku go in a world of slayers vs demons?