33 kills no S?

That's because, as far as I know, it's based on player average scores per champion. If you play Braum and win at 6 kills and 0 deaths, it has much higher value than known killers with the same score like Yasuo or Lux. Naturally, deaths decrease your overall s ore by quite a bit. Not to mention this system also takes into account your cs score relative to the game length, so it's possible gour friend got his rank from farming like mad.

he had better CS and better objectives and stuff than you had... you only focused on KDA