DonnEll
My theroy: he can leave befor doing the third evolution and tell them he will be going for a long time and tell them to keep recruiting people and keep doing quests so they grow stronger and he will still be technically the leader of the group of the adventure group in the adventure guild which means he will be able to auto-farm quests while he’s in the god continent.
so I have a few Guesses for what he will do with the fruit I will start with the least likely. every time he evolves the fruit's limitations reset and he can eat them again ( her unlikely but still) next off is that he sells them to gain influence and some money for his group which is unlikely because it would draw suspicion third he will give these fruits to people he wants to befriend. and the most likely one in my opinion is they are quest items that can be used later