Heir's Burden
Max wasn't able to use his force in order to drag Jason away from his current path because too many students had been watching them.
The only thing he could do was to pray, that his great-grandfather wouldn't beat the sh*t out of him, because he'd disregarded his well-meant advice, which some may even see as an order.
He was suspicious about Jason, who seemed to know his great-grandfather which not many people on Astrix could claim, let alone youths.
This was weird, but Max couldn´t find a logical reason for this scenario, except that Jason´s background was forged.
In the end, he convinced himself that Jason was from a large ancient clan because it was easier for him to comprehend that an ancient clan's heir disregarded his authority than a 'nobody.'
Considering this scenario to be the reason for Jason to be acquainted with his great-grandfather, made it much easier for him to understand everything.