If this is social security disability income then it would NOT be reported on your tax return. If she files a tax return then she would report this income on her tax return. If this is the only income that she has, she wont be required to file a tax return.
If you are both receiving social security benefits and her benefits are included in your check, you still would NOT report any of her benefits on your return. You would only report your portion of the benefits on your tax return. Although you dont claim her as a dependent, this FAQ has helpful information. https://ttlc.intuit.com/replies/4767362