Maybe allowing him some privacy will be beneficial to him. Not so he can do "that" whenever he wants, but maybe as a way for him to start having his own life and developing himself. A sense of privacy lets of be ourselves and relax.

I think you are very justified on the water usage and electricity. An hour long shower everyday is expensive and a waste if he isn't actually showering.

I'm sorry about his father. That sucks that he has to deal with that too. I was the type that bottles things up. My dad was very empathetic and could tell when something was bothering me. He would ask a billion question until I told him what was going on. In some ways it helped and now I tend to bottle things up less. I hope you find a way to work things out.