Normally a foreclosure sale (if done properly) extinguishes prior mortgage, liens and encumbrances on the property. Do you know if the title company knows the lien still exists on the property because of the prior NFTL or assumes it because nothing has been filed by the IRS extinguishing its lien against the real estate?
I’d really look into the foreclosure first to see if the IRS had notice. If yes, than probably you will have to contact the lien unit to get something stating that the lien does not apply to the former residence. If not, than your client has a title issue that will need to be addressed (still thinking about what next if IRS lien was not properly extinguished).