While it is horrible that this poor snake was neglected, I think you are overreacting a little. Ball pythons are pretty tough and can withstand long periods without food.

As others have said, get him setup in a secure enclosure with some dark tight fitting hides and leave him alone for a week or two. Feed him once a week and then start short handling sessions. Eventually he will learn to trust you again. Don't worry about being bitten. Ball python bites are a regular joke on this forum since they are so minor. They barely break the skin and after a few hours you can't even tell where they bit you.

Don't be scared.

Feed the snake.

Give him some time to chill.

and most of all, Relax!