That's a good roo, he's protecting his girls.
You just need to set him straight, that your not a threat to his girls, easier said than done and may be too late depending on how old he is.
I don't have a roo so I can't give you advice on how to do that.
I have heard if you spend a lot of time with them from day 1 that they are more likely to not see you as a threat when they mature. But every roo has their own personality.
My neighbor had a banty roo my mother gave them that was at the bottom of the pecking order in my mother's flock. He turned into the meanest roo. I couldn't go to my neighbors without being attacked. I had to call and they would lock him up, so I could come over.
Good luck. GC