User blog comment:B214/High School DxD DX.4 discussion/@comment-30924344-20170812140418/@comment-30924344-20170813145619

Oh I said Saji's dad was a teacher as I translated that quote just on it's own [may be incorrect so he may still be a teacher] but it would mean after the accident, Saji's father had to resign from being a teacher. Saji's mother is still a museum official or may have resigned too.

Also I seem to have found something about Issei's father, specifically his possible name.

兵藤一誠眷属事務所

Google translated this as ""Hyodo Kazumasa Departmental Office" and Kazumasa is a Japanese male given name.