Aside from the fact that the older dude finally decided the jealousy over a girl in the past was worth letting go after what Miyagi did for him during that typhoon or whatever kind of storm that was as opposed to insisting on a fight to the death, the fight between the title character and the younger one seemed to be about the same thing that the first one got into it with John Boy in the first one except that he was threatening to kill the girl that I thought he had some crush on. Personally, if some dude was dating a girl and thought I was talking to her too much, I'd do my best to do permanent damage to his reproductive system; and if she wanted him, she could have him. I hope the third one doesn't turn out to be over some girl and that the last one Morita-san made wasn't some glorified cat fight between the same dude. If I had two girls wanting me that bad, I'd be trying to make equal time for both of them.
Take care and God bless