you dont really know how well kuma knows dragon,sure they know each other and kuma knew that luffy is his son but you cant be to sure about how they know each other,from what kuma say it seems like he have respect to dragon…
i still do think kuma will do something diffrent in the marine ford when wb will come and also luffy,dont forget what he told luffy before teleporting him...
im sure luffy will try and beat kuma once he sees him,but kuma will just take him down...
moria also looks like he is ready for action,maybe he will want a rematch with luffy?