My kids thinking

(2 boys ages 7 and 8)So yesterday i picked my kids up from daycare , they walk with a daycare teacher that picks them up from school to daycare. As they were walking my 8 year old needed help with his backpack, he weighs 40lbs and his backpack is about 7-10lbs with all his stuff, he can't leave it at school in case of covid. So he got help well this guy(7 year old) decided he would throw a tantrum and it isnt your *screaming, kicking etc. No, he left his backpack as they were walking on the sidewalk. I got to the daycare about 1hr later to pick them up, he played dumb looking for his backpack for 10min, only to come and tell me he actually have left it in the side of the road(he only carries a folder with 5 pages of work,his homework). My info is in the backpack , his schools name/teachers and room number is in the paperwork that was inside. I was so mad at the point were i said nothing. We went down that street and saw nothing. We got home and i asked him where he had left it again he said the sidewalk so i was hoping someone would call (It's a brand new backpack) but nothing.. I'm hoping they would at least drop my kids belongings at the school but I don't believe that will happen. I explained to my son a couple of things and asked him to go on and put his brothers backpack on... I asked him what do you feel? It's super heavy he said... Did he need help with his backpack? Yes he said. Did you need help with your backpack? No, I didn't i just thought it was unfair, Do you think its fair that he has to carry a backpack so heavy, and you dont? I didn't know, he said. Exactly you never know what a person is going through unless you put yourself in their shoes. I have a backup backpack from last year but this week he will use a store plastic bag. Some may think its "cruel" but maybe he will appreciate having a backpack to carry, yes its a replaceable thing but little things add up and this is a one income only household I'm bearly making it and hopefully he takes care of his things.