Raise the flop for value if nothing else. Make a decision on the turn after that.

Now look at what's happened here: SB donks out into 2 opponents, which usually ins't a pure-bluff (and there's not much to semi-bluff). On the turn he is neither folding a 6 nor a J. Putting 2BB into a 5.5BB pot when you've got about 25% pot equity and opening yourself up to a 3-bet from a 6 doesn't seem too hot here.