I'm so sorry for her and the family's loss. It's sad when one's life has been snuffed out at such an early age, whether gestational or otherwise. I've never heard of anyone making a quilt in remembrance of a gestational loss. I've heard of remembrance quilts for older individuals, but why not? If that's how she wants to/needs to grieve. So be it. Very caring of you to offer.
Will you somehow honor her other losses too in that quilt? Not sure if that is something she's be accepting of, or if it's just for this little one... Any loss is hard. No matter what number it is. Maybe as, this may have been her last one? Not really knowing all circumstances; her age, the ages of her other ones here and in heaven...
We never know what is to be, rather who is to actually make it to this world, in which form. Sometimes the wee ones who don't, have a big impact on us and others. I hope she's doing as well as can be expected. I wish her and your family well in this time of loss.