Is there something done about alts

So i reported a guy for him calling me "retarded", "useless", and pinged me the entire game. All the while he was BMing the enemy team like the Ali sup he said "Your already better then 95% of Alistars in silver" just cause he W' in but forgot he was out of mana (i give the benefit of the doubt). But im not sure if he will actually get banned. He claimed to have alts and that he is a ELO booster. Does riot do anything about the alts or is it actually legit where people (like him) can make alts just to be toxic (he also claimed that that is what his acc was for that it was just a toxic acc)

If you need to see the convo in the end game chat room i can post it if you want