I'm in a 10 team league and the guy who has Bynum also has Eric Gordon and John Wall! We only have 3 bench spots - so he's got 3 injured guys there... he's at the bottom of the standings but if those 3 come back he could come home with a wet sail.
Dropping Bynum depends on your team your league, the free agents available and so on. If you drop him how likely is it that someone else picks him up and stashes him until he does get healthy?
IF you need a quality big man why not wait? You've kept him this long and I seriously doubt there is any big man available that could put up the numbers Bynum can