To claim the children as your dependent, a couple of requirements would be that they would have to live with you for more than half the year and you would have to furnish over half of their support. Also, they cannot qualify as your daughter's dependent.
You can read this TurboTax article to learn more. If you think they may qualify, you can enter them in TurboTax and the program will ask you questions to help determine their status as your dependent.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"