Is it an elementary school story? (I'm not sure this would work as a 'when I was young' page for a high school story.)
Besides a lot of missing commas, the big thing for me was it was unclear how many brother's there were, and who was who. I finally got that the unnamed brother who gets all the attention was the one crying to mamma and wasn't a third brothere - I think the dinner call threw this off. Why would he wait to tell mama? How would Adam forget about the brother he just hurt in space of two minutes? The mom could have easily cleared this up by calling her kid's names vs. just saying "kids."
Also, it's not like Adam is being unjustly sent to his room, so the characterization of the younger brother as a "monster" for validly claiming his brother hurt him - especially when it is implied this has happened before - makes for a very unreliable narrator. The fact the main character refers to himself in the third person in his own thoughts only increases this vibe.
Which could work. A school story with a boy set on proving himself a hero but who messes everything up and hurts everyone with his dellusions could be interesting. It would definately subvert expectations. If that isn't intentionall, though, and you want a sympathetic main character, perhaps reframing the scene as an accident or making it clear that his brother is a baseless tattler would help.
[It's also odd that the thing he loves most is sweets, lots of sweets, but he calls his brother's speech "disgusting sweetness." Perhaps a different descriptor would be better.]
But, the missing commas:
After back, before beaming.
After dragons, before and.
After somehow, before he. After it, before too.
After kiss (this should be a comma, not a period.)
After was and frankly.
After huwts (this should also be a comma, not a period.)
[Also, "the grownups" is a little ambiguous. If he means grownups in general, perhaps drop the "the." If his dad is in the room, too, we should be informed of that. But if it's just his mom, then "she" would be preferable to "the grown-ups" since she is just one person.]
After ptotestations, before you're.
I've heard it, though it isn't common so might be British. I think it means something like unfair or difficult-to-deal-with nonsense.