How do anencephaly babies survive when they have no brain?

See below. They have a brain stem, which will control breathing and heart rate.
They don't survive. These babies expire within a day or so of delivery.Like several other fatal birth defects,(absent kidneys,lack of lung development) the remaining body parts are nourished by the placenta and can make it to the end of a normal pregnancy and delivery.After they are delivered, the demands of independent living will end their life.