Wow...2 guys posting in the same thread about being under 6' tall and weighing 260. Both have weed-related names. My math is pretty good.
Put down the dope, put the bags of chips away, set the remote aside, step into the gym and MOVE your asses before you have coronaries!!!
Side-note...if you can get inside, remember, powerful punches come from your legs...keep your elbow close to your body, lead with your shoulder and don't over-extend your elbow. Leading from the shoulder will force you to thrust your entire body, from the legs, into the punch creating insane power. And keep your hands up at all times. Any punch to the knockout zone, deflected by your hands even slightly, will result in no damage.
Follow these simple steps or plan to get wasted. Your brother is trained...if you come in flailing, you're toast
And for god's sake, make sure your thumbs are outside of your fists and not tucked beneath your fingers!