transferring a Sheriff sale

[Fahima Hilal]

My client is in the process of buying a property from an owner.It turned out that the 'Owner' was actually a winning bidder at a sheriff sale. After agreeing on a prize to transfer the winning bid to my buyer, we found during title search, there are tax liens .The seller wants my client to split the lien with him (around 11k ) . I feel it is unfair as there was no mention of any liens or additional expenses while negotiating on price.

What is the liability of the seller if my client backs out? What else could be done to redeem this without additional expense to my client?