It's good that you are trying to help. He is shedding in pieces because ball pythons need more humidity (50-60 %) during shedding ti shed properly.

1: Covering about 3-4th usually works pretty well. Mist the enclosure everyday. A damp towel will also work but may be more of a hassle for you.

2. Soak him for up to 20 minutes in water that he can lay in without having to strain to keep his head up. So like deep enough for him to be mostly submerged. You only need to do this really when he has stuck shed pieces though. Too much soaking isn't good for them.

3. He shouldn't mind if he can sit comfortably. As you could imagine he would be very scared if he had to swim.

4. Yes.

More info about your setup? What are the temps? How are you measuring them? Pics of him/the enclosure? How often are you feeding him?