>He has told me stories about planes going down because small fires that result in a crash.
Plane crashes aren't kept secret. As far as I know, there are no instances of an in cabin fire causing a crash on a modern airliner.
The fire you linked to was caused, most likely, by faulty wiring in an inaccessible part of the plane. A fire that happens inside the passenger cabin is likely to be detected immediately, and the crew have a very good chance of extinguishing it. It's also worth noting that the same kind of accident is unlikely to happen now owing to the additional safety measures that were mandated following the investigation.
So, yes, a fire on a plane is a big deal. But the actual chances of a plane being brought down by a cell phone that catches fire are pretty small.