He's stupidly easy and obvious to do for this. Kareem is really just a nice dude, he wants to help people out, he'd dependable, he works hard, he's honest, etc etc. Frankly a textbook Hufflepuff, there you go. Gryffindor would be his second, because he does have that sense of chivalry and is brave, but not rebellious. Well...he's not rebellious in the sense of going against group sensibilities, he just wants to fit in honestly. But he's not daring, he isn't defined by a sense of adventure, so Gryff would only be his second. Ravenclaw next because he does like learning new things, but he doesn't have the patience or itnerest for the sort of extended long term study I think Ravenclaws need to be capable of. Slytherin last because...really he's got nothing Slytherin about him.