I would switch, but if I did, my friend would give me so much crap
Good news!
After the Patriots collapsed to miss the playoffs, losing 5 of their last 7 including an all-time debacle against the Raiders that will be replayed for decades, you can now jump ship from the playoff-bound Dolphins to the couch-bound Patriots with a clear conscience! I'm sure your friend will be happy to welcome you to Patriots Country as you both watch the Dolphins in the playoffs.
You'll need to do this quickly, though. You don't want to wait for the outcome of Sunday's game before choosing, as that may make you look like (more of) a fairweather fan.