I would do this...but this is just me... If I had a roo from a neighbor that been causing problems with my chicken, I would be ready for him the next day...WITH A TRAP! A live trap mind you. I would catch him and cage him and then, when he is caught, call the neighbor up and have them come pick the roo up.
Since your neighbor is a friend, he should be very cooperative on the situation. His Roo injured your Roo and been harrassing your hens. If he is planning on making the Roo Dinner then offer to help butcher it or ask if you can do it for him.
No. Take a crate or a cage. Wait until the two Roos start towards each other, surprise the neighbor's roo and crate him. Not going to be easy but it's worth the shot.