Wife is not Catholic. It has taken a great deal of encouragement to get the father to bring the girls to Religious Education. The youngest is in 3rd grade and the older one is in 6th. They have absolutely no formation in any faith, so we are starting from scratch.
Keep working on them! At their age, they'll probably eventually pester their mom into letting them be baptized.
It sounds as though the mom is not just lukewarm or inattentive, but actively resisting. Is she not just non-Catholic, but anti-Catholic? Mixed marriages are always tough . . . even when it's as slight a difference as Methodist and Episcopalian (which is how we started out).