You must ask her what is the particular issue or reason for the appraisal. At first blush, it sounds to me that the IRS is considering whether there is "inurement" due to her living in a house owned by her non-profit. (benefiting from the non-profit status)
Secondly, contrary to prior posts, you can and should use a simple FNMA type report for a non-complex residential property. The IRS likes it simple and comprehensive.
Next, make sure you use the IRS definition of Market Value, which should be included in the prior hyperlink. If not, Google it.
Lastly, an 8283 form is only good in relation to a non-cash charitable contribution, such as a donation of a conservation easement. It has to be signed by the donor, donee, and the appraiser. I don't think this is what you have. If you use it and it is not necessary, you may do more harm than good.
In conclusion, when doing an appraisal for the IRS, you should always have a letter of engagement that you prepare AFTER you have had a thorough conversation with the taxpayers tax-advisor. Make sure you cover yourself for post appraisal interviews via phone and in-person at the IRS office.