Well senegals are mostly blind anyway so it's really not that much worse off. Maybe give it some melafix to help its sockets heal up and as long as it will still eat it should be fine. You just might have to give it a little special care and make sure it gets the food.
FH ARE SUPER NASTY,my Fh still bosses my big cichlids around,Sometimes they go back,buy Fh are Very Persistent!
Even if that worked,It would have been a time bomb anyway,Fh would of got him eventually..
I had a common Pleco over a foot,his skin was real coarse like sand paper,I put a smaller Fh in a with the large Pleco in a 150 gal,about 6 months it lasted,soon as the Fh got big,bang I find my plecos eyes RIPPED OUT N DEAD....