Sql databases usually come with their own date types that are implemented with integers behind the curtains. They take up less space and are easier to sort than text fields.
EDIT: also I wouldn’t consider this egregious. If the Senior explains and the person was happy to learn something then that’s a good outcome. If they are stubborn about it, then that wouldn’t be great.
In the spirit of nitpicking, class A, B, and C referred to specific address blocks, not network sizes. A /24 in the class A range was still class A rather than class C.
Perhaps try giving them 4 future days off in exchange for working two weekend days. Weekend days are more valuable than weekdays because your family is free from work/school and there are more events.
EDIT: also I wouldn’t consider this egregious. If the Senior explains and the person was happy to learn something then that’s a good outcome. If they are stubborn about it, then that wouldn’t be great.