Oh my...what an aweful scenario. Worse, when the owner isn't home, and the cats perished. Mobile homes have been known to be like match boxes...high fire hazards. We had a house fire 2 years ago, and I hope to never live through anything that traumatic again. It started in teh chimney, and fortunately my hubby was quick thinking enough to run out and get the fire extinguisher, but it caused some fire damage, and tons of smoke damage. We got 2 dogs, and my step-son out and waited for the fire trucks. Took close to a year to move back in.
I always find myself preaching to people about keeping their house insurance policies up-to-date, know what your contents is, check your smoke detectors every 6 months, and have a plan if such and unfortunate thing is to happen.