Can we get an update on the leaver buster system?

I've been duoing with a friend of mine the last couple of weeks. He's gotten to the point where he isn't sure he wants to play with me, because he thinks there's an ELO problem. You see, when he duos with me, we get a lot of afkers. 3 out of the last 6 games had a 4v5 situation, and it never seems to go in our favor. One of those 3 games was 3v5. Xin Zhao in one of those games had 27 farm in the jungle at 35 minutes, never once ganked, didn't even finish clearing jungle camps, and didn't cover mid lane for the afk Annie (or whoever it was). We honestly thought he was a bot because he never spoke except to say ff when he prompted a surrender vote at 20 minutes. I'm getting demoralized. What's the story with the supposed updates to the leaver buster system?