how do i talk to my egotistical teammate?

I got this game to play together but as we play together more often i notice 2 things…
* he waits until i get 8 or more shots on someone and lands the final blow to steal credit the whole game, barely getting his own so i have 9 assists and 0 elims and he has 9 elims and 0 assists

• he never revives me because he likes the glory of winning solo which is admittedly impressive but annoying when i spend half the game watching HIM play when i could have easily been saved in every single match where I'm down

• i tried asking him to stop stealing my kills and target his own players because it's a chronic issue, but he got immediately pissed off and said "we're supposed to be a team, that's how teams work" and then tries to act sagely and give deep criticisms about my personality flaws and how they impact my gaming. I'm new to fortnite, been playing for 1 month, but i get an average of 9 kills when i play solo. I can't talk to him without him staring down his nose at me and treating me like a child, is there a way i can talk to him without him getting defensive and condescending? He likes to show off but it makes it so that the rest of his teammates sit on the bench and watch