Laughable matchmaking

I guess then that my question would be, was this guy solo queueing or was he stacked with those diamond teammates? Beyond that I'd like to know what his mmr is. Like I said, is he a "legit" left side player or is he a plat/diamond player in the early stages of his grind? I know the matchmaker in this game is terrible, but there are factors that could account for that match.