He really looks up to you

You don't see it, because siblings never show it, but he really does look up to you. You guys get into the worst fights over the stupidest shit, but when you're not around, did you know that he talks about you the most, and he always has a smile on his face when he does? Yeah brothers can suck, believe me I know, but hold onto him tight, learn to let more stuff roll off your back, and if you look close enough, through the snarky comments, and constant debates, I think he's insecure.... I think he's insecure about himself, and he wants to prove to you that he matters, and that he has a place. To you, you might feel like you had to fight for everything and things always came was easily to him, but for him.. I think he might feel like he's constantly worried that he won't be good enough, or one day maybe his "smarts" will run out or I don't know I'm hypothesising here, but my point is, take it easy on him. I think out of all of us he misses you the most.