Yuuji 's family is by no means extraordinary.

The Itadori family is one of many perfectly normal, perfectly civilian families. They are not mentioned within any particular records, and Satoru has indeed read through many. They are one of countless normal families, living about their lives without knowing a thing about what lies beneath that veneer of normalcy.

Itadori Jin was a perfectly ordinary man, aside from his premature death. Itadori Wasuke, too, was a perfectly ordinary patriarch, having lived an adequately long amount of time compared to his son. A tragic family event, certainly, but by no means something extraordinary.