To lose a child through a miscarriage is hard enough, but to know your child for a further 8 months after birth is awful and must inflict a pain that no one else can convey unless they have been unfortunate too.
To write this for your friend was brave and must have been tremendously difficult for you. You would have needed to place yourself in her shoes, or at least, within in your mind. How would that huge loss feel like. Imagining the tears, the fear, the knowledge that this loss would haunt you forever.
Well done for such a brave write and pass on my best wishes for the future.