I would not put another snake in his enclosure. That will stress him out and will make the situation worse. As for the water bowl I never see mine go into the water bowl either. he probably uses when he needs to at night. As for the eating sometimes my balls eat the but first. That to me isn't something to worry about. Honestly if he is eating okay and his temps and humidity are good he is probably fine.

You could try letting him be for a couple of days to give him alone time. One of my snakes is pissy right now. So I checked his temps, humidity and i am leaving him be for a week. That usually does the trick for me.

Keep me updated