You should treat this as gifted property. Regardless of what the land records say, your client didn't pay any money. The following is the from Q&As on irs.gov but it's also stated in the regs and pubs:
"Question
What is the basis of property received as a gift?
Answer
To figure out the basis of property you receive as a gift, you must know three amounts:
The adjusted cost basis to the donor just before the donor made the gift to you.
The fair market value (FMV) at the time the donor made the gift.
The amount of any gift tax paid on Form 709, United States Gift (and Generation-Skipping Transfer) Tax Return.
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.
Note: If you use the donor's adjusted basis for figuring a gain and get a loss, and then use the FMV for figuring a loss and get a gain, you have neither a gain nor loss on the sale or disposition of the property."
You need the FMV at the time of the gift. And to file a belated gift tax return. And just for the fun of it, to investigate how FIL sold property he did not own. Or you can take the substance over form route. Property still belonged to FIL, he has sold it and is now gifting the proceeds to his daughters but keeping the loss for himself.