I pray you'll urge your daughter not to end the life of her unborn child, in spite of the difficult circumstances your whole family is facing. All human life is sacred, and God's words to Jeremiah apply to every person: "Before I formed you in the womb I knew you, before you were born I set you apart" (Jeremiah 1:5).
Instead, encourage her to explore all options, even if some are hard. What seems to be the easy way out of a problem usually isn't the right way -- but the right way is always best, because it's God's way. Countless childless couples, for example, would be delighted to adopt her child and give him or her a happy and loving home.
Beyond this, however, I hope you'll do all you can to let your daughter know you still love her. In addition, ask God to give you the wisdom to help her rebuild her life. Her life so far has been marked by bad decisions; now is the time to encourage her to make right decisions. But avoid harshness or anger; it could drive her away. The Bible says, "A gentle answer turns away wrath, but a harsh word stirs up anger" (Proverbs 15:1).
Above all, encourage her to seek God's will for her life by putting her life into Christ's hands and looking to Him for guidance. God loves her in spite of her past, and will change her as she submits her life to Him.