We could not remake because he was technically loaded in before 3 minutes,
A player has to be disconnected from the game for at least 90 seconds by the 3 minute mark in order to be eligible for a remake. In other words, a player has to have exited the game by the 1:30 mark for a remake to be possible for that team (assuming that the disconnect happens before enemy first blood, when applicable). I'm pointing this out because it's a frequent misconception.
Unfortunately I'm missing the context of "He did it on purpose" and I can't discern if you mean that he wanted to screw his team over or if he AFK'd with the intention of letting your team remake the game. Regardless of his intention, he deserved to be reported for AFK/leaving the game since he didn't properly disconnect from the game and ruined that game as a result.