Luffy will bring Joy to Akainu and make him realise he's fighting for the wrong side/for a perverted form of Justice and that Akainu was wrong/fooled this whole time, similar to how Javert realised how blind he was in Les Miserables or something like that.
Luffy has his sake cup brothers and Akainus name is "Sake Cup" too (Sakazuki). GODA! (Fujitora should be Akainus brother unironically too.)