I have this friend
This friend is pretty good. They usually win their lane fairly hard and get fed. Unfortunately, this friend thinks that they should split push as a mid AP after they get fed leaving the team to fend for themselves. Other times, they just get cocky and dive into a team only to die, throwing the game. How can I go about telling them what they're doing is seriously stupid and that they need to learn how to really abuse a lead instead of throwing it constantly in the nicest way possible without sounding like a jerk? Thanks for your help :D