That "deaf" guy was in an episode earlier in the series when Dwight is picking up illegals to work for him and he's the only dude that sticks around
He's been in a few episodes. He was in the one where Pam and Dwight were battling it out for the business to stay in Dwight's building last season, and he was the photographer for the Christmas picture last season too.
Anyway, I don't know how I feel about this episode. I hate to say it, but I think it's best if they put the show to rest after this season.