Because Ben Cherington’s Red Sox have won over 90 games so far, it’s sometimes easy to forget about the guy who preceded him as GM. But then Theo Epstein comes back to Boston, and we suddenly remember those two World Series championships. Epstein returned the other day for the opening of the Brookline Teen Center, the town’s new hangout for kids. Also there was Theo’s brother Paul, parents Leslie and Ilene Epstein, the center’s executive director, Matt Cooney, congressman Joe Kennedy III, former governor Mike Dukakis, and singer Eli “Paperboy” Reed, who performed a set for the crowd.Mark Shanahan can be reached at firstname.lastname@example.org. Follow him on Twitter at @MarkAShanahan. Meredith Goldstein can be reached at email@example.com. Follow her on Twitter @MeredithGoldste.