It can't be he cheated playing, because he only had one or two matches played in total.
If it's cheating you're banned for "fair play"
Abuse is kinda hard to be banned for (as long as you're acting like a normal person, and he seemed to). Usually you get some warning(s) or mute(s).
Maybe a mod overreacted.
I wonder too. His account says "closed by abuse", but that could mean many things. Here in this thread he didn't break any chess.com rule.
It can't be he cheated playing, because he only had one or two matches played in total.
Before getting banned he said there were people here in chess.com trying to kick him out. It looks that they succeeded in the end.