This is a story trophy and cannot be missed!
Staying airborne, dodging projectiles and paying attention to his
movements and learning the rhythm to when he's vulnerable are key to beating him. Gadgets can be helpful especially with the new suit ability you've just unlocked but are unnecessary, I personally didn't use the gadget wheel at all during this fight.
It ends in an emotional cutscene that happened to coincide with some dust flying into my eyes and making them water. I swear I didn't cry....
After completing Act 3, you can go and complete whatever challenges, collectibles, activities or side missions you may have left behind.