Have you seen the Riggs Family blog? I came across it about a month ago...There is so much that could be said, and by people far more elequent than I, but I just wanted to post the link and encourage you to pray for this family. You can get updates on Facebook and Twitter as well.
Pray that God would continue to strengthen the family as a whole and Abby specifically, for Abby's deliverance from the cancer, for God to be lifted up and treasured by His children in the midst of this trial. Rejoice in His kindness thus far - Abby was born, she was adopted by a loving family who seek to honor God and trust Him, she has received medical care. These are all tender mercies from our Father. Rejoice that Abby's care is ultimately not in the hands of men and women, but in the Lord's. If He heals her, rejoice in His kindness. If He calls her home, rejoice in His mercy - for she shall no longer suffer and there is no better place to be than with the creator of the universe.
Friend, would you join me in praying for Abby today?