The mother is dead, medically and ethically. All artificial machines can do is keep her lungs and heart beating. Is that enough to provide what a fetus needs to grow and develop until they are at a stage where they can live outside the womb?
the medical answer is no... and the docs agreed with that
It has been done before.
Here is another case where the family was NOT dead set on killing off the innocent kids: http://www.cbsnews.com/news/brain-dead-mom-gives-birth-to-twins-while-on-life-support/
It is not common, but children have been saved in cases where the mother dies prior to viability.
In this case, the father wanted the baby dead from the get-go. I can only imagine why... I bet a lot of stuff happened behind the scenes that we will never know.