Don't feel bad if you decide to cull him or rehome him for the peace of you and your hens, if that is what would feel best to you. I know it is not easy, but he has had a better life there with you than he would have gotten anywhere else already.
There are a lot of methods to tame a rooster. I would try some of those and if they don't work you can make your decision about what you want to do then. Just search the term "aggressive rooster" and you'll find a lot of info.
Aggressive roosters are natural, in some respects. I have to have a...