Her winnings are income to her. If more than $13,500, she must file a tax return, report the winnings and pay tax. If half her social security plus her winnings are more than $25,000, part of her social security will also be taxable.
If her winnings are more than $4700, you can't claim her as a dependent this year. However, if you still provided more than half her overall financial support, you can still deduct her medical expenses that you paid, even though she is not a dependent this year.
You would never report her winnings on your tax return.
