Schedule D is a popular answer today for the sale of homes.

What was he storing?  Inventory and business equipment?

You need Sch D, not the 6252.  This is how I would do it, I like to keep my sales price actual just in case a 1099S was issued, I want them to match.  Use the 1099B worksheet.

This is perfect. Thank you so much. I really appreciate it.

I do not need to report depreciation? He is a real estate professional and he is insisting that I need to.

He is a bit of a hoarder!

Has he been depreciating it for the last 17 years?

No.

I would also explain that the depreciation recapture on the sale for the depreciation he never took over 17 years would decrease his basis and create a larger capital gain. Sounds like he really does not understand depreciation.