"The game forces a 50% winrate"

I have a buddy who is stuck in Silver. He told me over his last 100 ranked games he won 51 and lost 49 and he says this is proof that the game is rigged and forcing him to stay in Silver.

I for one think that means the system is working. He's an average player and is always focused on his team mates mistakes rather than the areas he can play better, so it wouldn't surprise me that he has not improved at the game at all. He's staying in Silver until he's good enough to play in Gold