Another way to think about it that frames you for class problems using punnet squares is. "who is more likely to spread lethal X genes while not being affected with the recessive X gene."

Its the mom. Mom will pass out recessiveness like its halloween if she is a double recessive. You're still guaranteeing future generations deal with it by having her be a one Lethal X recessive. I like to think about this kind of problem like Moms are the probability enhancer and dads are the justifier that forces the issue insuring you have XX recessive. For those heading to college they will typically not tell you its X recessive but just say Colorblindness or Hemophilia A and you have to realize those are recessive X genetic disorders.