Having her contact the IRS for her official 2015 transcript sounds like the right next step. You can do that online here: https://www.irs.gov/individuals/get-transcript
I would expect the IRS "Where's My Refund" tool to be tax year specific, meaning it may only be showing 2016 refund information at this time.
You may also want to contact her spouse/ex-spouse if she was married as of 12/31/2015. It's possible a joint return was filed.
If it does turn out she needs to file her 2015 taxes, you can download older versions of TurboTax here: https://turbotax.intuit.com/personal-taxes/past-years-products/
