I've noticed that my advisor (non-native) sometimes makes minor spelling/grammatical errors in academic papers. I believe this is due, in part, to the fact that until very recently, nobody in the lab was a native speaker.
Is there a way that I can bring this to my advisor's attention professionally? I would like to also let him know that I'd be happy to proofread any of his papers prior to submission, if he would like. Obviously, I make mistakes as well, so I'm sure I will make similar errors at some point in publications, but I would always want someone to point it out to me.
Edit: I should note that I have no intention of trying to correct his spoken or informal English.