It's too late for Fujitora to be an enemy for straw hats he's on the side of marines like Smoker, Tashigi, Garp, Sword members, first of all he genuinenly likes Luffy if you read the end of Dressrosa arc
Helped secure slaves even fighting Ryokugyu for what he believes is right
Openly implied he doesn't like the WG to a vice admiral, who deluded themselves to think they are gods Imu and Gorosei certainly would think so and they are at their boss
While Fuji doesn't even know the empty throne and the oath to it is a big fat fucking lie
Imu's reveal is gonna generate another huge rift across the organizations first we had warlord abolishment, two of the four emperor's replaced, Luffy, BB, Shira and Vivi somehow into play for Imu too, possible fallout among Navy, and we are having an Admiral with Gorosei member personally and 100 ships going to war in Egghead
Fujitora will have a similar role as Garp, Sengoku, Tsuru etc.