There is currently no deduction for school tuition other than post-secondary (college). I do have a suggestion for you though. If your daughter and her husband are coming up with a negative income, they are not receiving any benefit from claiming your granddaughter. They might consider letting you claim the granddaughter as a dependent (since she meets all tests to be you dependent as well as their's). Even further, they should have a tax preparer look at your return and their return for the previous year and see if you would have gained more from claiming her. If so, an amending tax return may be filed on both of your parts and may get you back some additional money that you could even share with them.
My best to your family. Please let me know if I can assist you further.