he and leah met in 2009ish and got closer over the years through working on a few projects together, so i think it's possible that he and charlie could've met at some point depending on when he came to the states? but maybe only vaguely if he lives in la like his sisters as seb lives in new york. he started dating leah officially almost three months ago and since they've been pretty attached, i'm sure there's more of an opportunity now for him and charlie to get to know each other better. plus, who doesn't like steve harrington? seb's 100% asked for spoilers and will continue to do so.