If you are going to fight with a relatively low output, just make sure you are out-landing that guy. You can shut down his output and accuracy, but make sure that you are clearly landing the better punches. Your brother's output was a bit low (end of second round was nice, good attack along the ropes). This was moreso the case in the first round but diminished a bit as a problem over the course of the fight.
There were a few times when the 1-2 wouldn't land because the opponent saw it coming and backed out of the way. Work your way in with the double jab and then throw the right hand. When he backs up so much to get out of the way, steal the space. Take what he gives you, and by contrast, only give up what you need to.
Move around more (laterally), not in and out so much. The opponent was there to be jabbed more. Move your head when you jab to avoid his counter jab.
I'm surprised they let you have cheek protectors. Most amateur bouts don't let that happen. Or I could be wrong.
I was gonna remark about the weight. I weighed in at 178 without having to cut any weight and at least one of those guys in the video there looks close to my size. I couldn't fathom ever cutting 13 pounds to get to 165. There was no fat on me I was lucky to tip the scales at the 178 limit.