@Faf - I don’t mean to sound sceptical because I’m not, and I don’t know you or your lad. But is your son a reliable witness? Do you trust everything he says? Are you 100% sure it’s what happened and he didn’t kick off?
I know when I was his age I was economical with the truth, so just a question!
One thing in your advantage is the frankly pathetic, lazy witness statement on the part of the member of staff. My reaction if I read that is “what, that’s it? That’s what you’re sending someone to court for?”
In the event it does go to court it will require him to actually say things in his defence. I am sure nobody wants for this to happen, hence my original advice to just settle, but if it does, he will need to be motivated and have the confidence to speak up for himself.
You’ve also received advice here from other seasoned and reputable posters who have encouraged fighting it. Those are also worth considering, although I am not sure in your situation it would be within my appetite to do so. It’s up to you to choose what to do, but do please keep us updated. This one seems a gross overreach of Nexus’ power.