By his grandfather, I assume you mean Hiashi, right. Sasuke's his sensei... XDDD I wish I could really see him trying to teach Haku.

Yeah, it is Hiashi. And Sasuke has a hard time teaching Haku, since he is extremelly stubborn like his dad. XD I thought it would be interesting to have Sasuke teching his best friend's son

Yeah, I just know it'd be funny to watch.

Yup Expecially because I made Sasuke obtain the same "lateness" problem as Kakashi when it comes to meet his students in missions

*pictures adult Sasuke coming up with a lame excuse for tardiness like Kakashi* (like this -->) Sasuke: Sorry I'm late, I got lost in one of my flashbacks. XDDD

That could so happen! And Haku would react exactly something like "Yeah right, I bet you got lost while reading one of those weird books again..." (Icha Icha Paradise)

O.O Sasuke reads Icha Icha now... Didn't see that one coming.

Kakashi has a great influence on his students

I guess so.