Property Owned by Sole Prop Lessor but Not Used In Business - Ordinary or Capital Asset?

Asking this on the behalf of my father but:

1. He is a taxpayer engaged in the leasing of real property (Sole Proprietor - Lessor)

2. He has properties under his name that are used for business, but also properties (some land, some land with improvement) not being leased and are being used as residence by relatives.

3. Are all properties under his name classified then as Ordinary Asset and subject to VAT? Even if they weren't used in business, because of his taxpayer classification?

4. If yes, what will happen if he were to close his business? Will the non-business Ordinary Asset eventually be reverted back to Capital Asset given enough time?

Thanks!