Everything is repairable. Like Chris said, the effort probably isn't worth it, it'll likely come back to haunt you later. Lots of corrosion there. Battery leak damage is very unpredictable. I'd do a repair like this for myself, but I'd never trust it in the long run for anyone else. But if you have the means and the knowledge and the desire to repair it yourself, go for it. I would be a good learning platform if you've never done board work.