Jay might be correct. There is a chance that his is 100% right, so check out what he says. One other thing I can think of is that the termite guy might have drilled through your slab to inject his poison under it. He might have incorrectly sealed them and you might have moisture actually coming up from under your house. This is kind of iffy though.
The symptoms you describe also sort of sounds like a classic humidity/condensation problem that is common in uninsulated slabs. I would wager that the builder of this house buried some scrap lumber under the slab that helped attract termites. He also probably did not put any insulation under the slab. When it gets warm and humid, the floor is cooler and you will get a wet, slimy condensation appearing everywhere. The only real treatment is heavy dehumidifying and/or air conditioning. Did your mother just move into this house since last summer? If so, this has probably always happened in this house. If she has lived there a while, and this is a new phenomenon, does her central AC now not work, or her dehumidifier? Is her clothes dryer vent backing up and injecting moisture into the environment? Check out all of these if you can't find what Jay mentioned. Livin on a Slab! Yum!