I went through the same thing about 7 years ago. My drives and other parts were stolen while under the care of a 3rd party. Luckily for me my father was in insurance for 30 years and helped me weave through the maze of BS. I initially got the same answer as your friend. I got 3 denial letters before they finally agreed to pay for my loss.
2 phases needed to be repeated in all written correspondance.
1. I suffered a loss of an insured item
2. I expect my insurance company to act in Good Faith. (Do a search on "Good Faith" and you will see it is legal term in the insurance industry).
Get a copy of the police report (this proves a loss occured). If no police report was filed by the broker, your friend needs to report the theft ASAP.
It may take a while, but your friend should be compensated for his loss. As long as premiums were up to date and proof of a loss exists (police report), the Insurance company must act in "Good Faith".