I think it's pretty obvious he was in the habit of permitting the children to access the work laptop while in Scotland, which is an issue in itself, then got caught with his pants down when they did so in Morocco on a redundant SIM.
The idea that it was a deliberate choice to watch on a work laptop to "avoid paying" doesn't stand up, since even if protocol had been followed and the SIM replaced as instructed, there would still have been a significant cost incurred, and there would have been no way to hide that from IT.
His kids did something they were in the habit of doing normally, only they did it outside the UK, either with his consent while he was oblivious to the obvious consequences, or without his consent. He then played innocent, his reasons for this are debateable, and lied after the truth of the matter was known to him.
Ultimately he paid the money from his own pocket, but he should still face sanction for the inappropriate and lax use of SP IT, and then lying about not understanding how the situation came about even after he did, in fact, know exactly how it came about, even if, as he maintains, he did so to prevent his children being dragged into it. I still can not see how this amounts to a "grift". He's been extremely foolish, naive at best, exposed as a liar, and should face consequences.