I agree that giving her space would be the best thing right now. It must be really hard, especially with a grandkid in special care, but what else can you do? If you text once a week and get no response, text once a month. I hope your husband keeps up the relationship he has with her so at least you can stay up to date.

Mother/daughter tension can blow up for seemingly no reason. A 16 year old having a baby is a person who is going through a mind blowing number of changes all at once. Instead of a gradual separation as she moves into adulthood, it's hitting you both all at once.