Depending on how much heat, it might not be so good on the plastic lens, reflector and switch mechanism. Unless he somehow got loctite in the threads, my guess would be leaky batteries welding the head to the body. I had this happen to me, but was lucky enough for it to be on the other end. Long story short, I had to use vise grips and replace the cap with a NiteIze switch.
KuoH