Is ELO boosting by duo queue allowed?

I recently played a game where our jungle played Olaf then took tp and went top. I was swain and had unsealed spellbook so I was originally going do what i could to Jungle, since he took my top role, but no one leashed and i couldn't kill a a camp so i just went top and shared experience. Our Adc went on then to completely murder the botlane to the point that even with no jungler we killed the nexus in 18 minutes and the adc ended 22 kills 0 deaths. I then figured something was up, so I looked up the summoners name and saw this guy ALWAYS went olaf top with TP he had almost 100% wins ALWAYS with one person extremely hard carrying his team, not him just someone. After a few games the person hard carrying is no longer duoing with him, but then another summoner name appears and he solo carries a few games repeat over and over.

Is this considered ELO boosting or is it permitted? Like technically I guess he is not doing anything wrong right?