Terms of service, and more generally - contractual, violations without 'material loss' tend to have no remedies available unless otherwise agreed to. Fun lesson I learned in a project with a dubious partner.
The mole shared access credentials - forbidden by Discord's ToS and by UK's law. This is very plain and simple to anyone with half a rasher of logic about them.
Were account sharing criminally illegal, then I think that would be the obvious first target.
So we're suddenly for abusing hacking legislation to prosecute people, just because in this case the target isn't sympathetic?