I can relate to Martin here. I had an asthma attack when I was around that age and it was pretty much the same thing. You started coughing and can’t stop, and it sometimes hurts to breath afterwards.
It can happen from dust or other such things, which is sometimes what causes if. And running around like playing sports, or chasing around your younger sibling ;), can easily trigger it. Like you said, you can’t really cure it, but you can control it.
Either way, love the story! Very accurate and tooth rotting sweetness between the bros!