I just realized this after reading through OP again to the current issue. But It never showed him getting killed by poison or whatever, but up to there its implied that he was defeated. But later on when BlackBeard shows up we find out that with the level 6 inmates that they together beat Megellan. So if by chance they defeated Megellan before he could finish Bon-chan then perhaps we may see him again. This is just speculation but also wishful thinking. Bon-chan always sacrifices himself for Luffy and I would love to see him in the New World.