Unless you looked it up in the Air Force writing regulation may have given him wrong info. For the Army AR 25-50 spells out two spaces after a period, I don’t know the Air Force reg.

AR 25-50...two spaces after a period are required by regulation in official Army writing.

AR 25-50...two spaces after a period are required by regulation in official Army writing.

AR 25-50...two spaces after a period are required by regulation in official Army writing.