what's the reason he's making the "gift" ? and there may be tax consequences because of the tax rules for the basis of gifts - both when you gifted it to him and now when he's "gifting" it back.
If the FMV of the property at the time of the gift is less than the donor's adjusted basis, your adjusted basis depends on whether you have a gain or loss when you dispose of the property.
Your basis for figuring a gain is the same as the donor's adjusted basis, plus or minus any required adjustments to basis while you held the property.
Your basis for figuring a loss is the FMV of the property when you received the gift, plus or minus any required adjustments to basis while you held the property.
