I didn't cry for either of my deliveries. I would have but I was in so much pain I had to focus on breathing not crying.
Since they have been born they can make me cry like no one else on this earth can. Not even my mother or my husband can make me cry in the same way.
If you are talking about post partum depression, the crying will continue until she can seek help and get medication, a support group, or a therapist. Usually a version of all three.