What's the threshold for someone getting punished?

Recently had a game with a really nasty player who was trolling, we had a terrible start (behind by 10) and with some luck scored two late game aces and took an inhib, after the first ace, we we probably played another 20 mins or so.

It felt like one of those great comebacks, all the momentum was on our side.

The entire time this person (our adc) just afk'd under a tower, didnt come out even after we had ace'd the other team.

Now, I know our team reported this person, and from all chat, likely the other team as well, but this person continues playing games.

At what point will this person see some punishment? (and idealistically reform)