Needed Help for Oscar !

[Aquatank]

Hey guys recently I had went for a trip to the ball for about 2 weeks an for that time I left the fish tank to be taken care by my Cousin Sister and when I reached home I saw that my big tiger O's has got little bit of swollen top eye I guess that he and my FH had got into some fight.
So guys help me what should I do an will my Oscar loose it's left eye here are some photos.

 

[jonclark96]

Lots of water changes and melafix will help if it is just a surface wound. I'd separate them if possible. How big is the tank? My guess is the FH will only get more aggressive as it gets older.