Ah. I don’t know how much a picture would help. I was asking because I thought it might help the people on this thread more experienced with injury than me.
You don’t have to kill your rooster. Just keep him separate from young cockerels. Though I wouldn’t breed him if I were you, as temperament can be genetic.
Looking at the video, it does unfortunately look like he could have neurological issues. I only have experience with Marek’s disease, not neurological problems caused by an injury, so I’m not sure what your next move should be.
The adult rooster does look like a game mix. Has he ever been able to live peacefully with another rooster?
I don’t think you should worry about your cockerel, yet. He seems to be recovering. Maybe you could take a video of him trying to stand to post here?