Did this all happen in one day?
Having an attack that severe can cause shock and having basically perfect water parameters is key for helping him heal and not have to deal with any other stresses.
Probably I do not have the exact answers, not as much experience with Cichlids.
You may need to add an amount of salt to the tank for his fins.
You may want to consider using Epsom Salts to help him heal as well.
more info here
https://www.aquariumadvice.com/forum...py-374191.html
I would think that medication might be needed. But also medication is hard on fish and can cause additional stress, at a time when stress could be detrimental to his health.
To some degree the fins should continue to grow if not infected. And they may not look at all the same as before.
Also if you can keep the light off for the most part, and if you can add some places to hide like stem plants or artificial plants in areas he seems to want to be.
Keep the uneaten food vac'ed off the floor of the tank, hoping it is bare bottom to keep it as clean as possible.