Protective cousin/brother?

Sooo... my older cousin is kinda protective of me. And I know he cares about me. Kuz he knows I'm small ( he's 14 like 5'3 and I'm 13 and 4'8 ). Whenever he sees me with my best guy friend he asks what I'm doing. And my cousin is like my big bro kuz he checks my eyesight. ( its really bad. W/o my glasses I can't see farther than 4 ft ) so he's like standing right near my face holding up 2 fingers and I say 2. Then he stands back like 3 more feet and I'm struggling to see what it is. I say uhhhh.... and he says well ok at least u tried. And he's also like my big bro kuz one time I went to his house for a sleepover and I asked if I can get "his" icecream and he said no. Then I asked why? And he said its mine, don't touch it unless u want me to kill u. Like wth?! Dude its ice cream! Anyway he's protective kuz one time we went to a skating rink for our other cousin and someone barely bumped into me and he's all like " did that person bump into u? They're gonna be sorry" why does he do this??