My Friend got permabanned for some reason, I just need an explanation

So my friend got banned twice, once was 14 days, same happened to me, then, in the second game, where he wasn't really being toxic, he got a perma. I thought there were supposed to be escalating levels of ban. (ie: 1 day, 7 days, 14 days) I just don't get why it was so sudden. i can understand the summoner code, but I see toxic people everyday that don't get banned for small stuff, like a line or too. I can't tell if it's people who don't get "jokes" or people who just report people. I don't think riot is an unfair company, but the way they do stuff can be a bit confusing from time to time [sg-zephyr]