Is halo reach OK for kids to play?

Yes. I only remember it swearing like maybe 3 or 4 times in campaign. It's online play that swears a lot. And the swear Words it said in campaign were only the d Word, and maybe the s and a Word. But they only say them like once or twice in the whole campaign. But there aren't any f Word saying or anything. So that's good. But if the kid is pretty mature, around like 11 or 11 at the youngest, then I don't see a problem with it whatsoever.