I live in a semi tropical area near the ocean with expensive land prices. During the real estate run up many older homes on ocean or near ocean lots were purchased on spec. When the real estate house of cards collapsed the houses were basically abandoned and the empty structures deteriorated quickly from the bugs, brutal sun, the humidity and salt exposure.
Even minor roof leaks in a closed house with no a/c in 95 degree weather with 100% humidity can destroy a house pretty quickly. Don't know if that is the case here but what she did is not unprecedented if the house had extensive termite damage, mold, leaks and/or rot.