Steven is right, there stuff is very heavy. Our troop purchased 4 of the 4 man tents before I became the scout master. They weigh 10.5 lbs tent, poles and fly. You can't break down the equipment by 4 (2.5 lbs per person) so one of the boys has to carry 4 lbs of tent and another the fly and another the poles.
I switch them to 3 man tarps that weigh 1 lb. each and set up with a trekking pole. They cost the same as the alps tents and are 1/10 the weight.
Now a 80 lb boys doesn't have to carry more then necessary.
At 80 lbs the boys should carry no more then 16 lbs. If he gets a Alps pack at 6 lbs, Alps sleeping bag at 2.75 to 3 lbs, and at least 3 lbs for his share of the the alps 4 man tent that would put the boy at almost 12 lbs for the "big 3," leaving only 4 lbs for 3 season clothing, food, water, kitchen gear, ground cloth and other essentials. There are not to many 11/12 year old boys with "lightweight" clothing and other gear.
But if money is an issue there are ways to make some of the Alps stuff work.