Several other JP cases similar to these have also the same repercussions (as mentioned above); added that we don't know the entirety of the context in what situations he was using his accounts for, contractual obligations and details does matter and not simply becoming a non-issue.
Playing on someone else's account is also against Riot TOS (a fact that honestly more people didn't even know about,) so it's still somewhat baffling that most are brazen enough to do so.
1.5. Can I share or sell my account or login credentials? (No.)
When you create an account with us, we require you to select a unique username and password (collectively, your “Login Credentials”). You agree that:
You can’t share your account or Login Credentials with anyone.
You can’t sell, transfer or allow any other person to access your account or Login Credentials, or offer to do so.
You must keep your Login Credentials secret.