Fathers *and* mothers are vital to all homes.Any kid who grows up without either one will suffer...substantially...for the rest of his/her life.
My little sister,who's a grandmother now,*still* speaks of how sad,difficult and frightening it was for her after our mother died when she was 16.And she says this in spite of the fact that our Dad did everything he could for her.
She must have been very close to your Mom.
It's nice that they had the time together though.