The IRS doesn't need any documentation from you or your aunt. You request a distribution form your FSA, whatever their procedure is.
Then you claim it on part III of form 2441.
You do not need to give your aunt a W-2 or 1099-misc. But, she does need to report the income on her tax return. She would normally report it as self employment income. But, because she worked in your home, and the amount is less than $2200, she can report it as Household employee income and avoid self employment tax (social security and medicare tax).
