If its freshish & still damp - I would force dry / ventilate with whole room dryer then thoroughly sand and seal with a couple of coats of decent varnish or laquer - this will save your prospest a fortune not to mention major upheaval and poss finding more nightmares under the floor. A fair price for this service will work out around 25% (or wahtever you want) of his potential replacement cost of regular pine wooden floorboards - his saving can then be turned into a good earner for you...
Regards
Stu