The older man has three major disparity of force reasons on his side.
1. Multiple against one
2. Younger against elderly
3. Surprise attack/breaking in
Don’t forget the crowbar and the fake gun.
The problem he has is that he apparently shot the hood while he was still outside the residence, and may have been still on the fence he hopped to get in the yard. Then, wisely in my estimation, he refused to give police a statement about the shooting.
When a shooter won’t talk to the police after killing someone in the yard, somebody is getting arrested.