Well, I don't know, I guess my question is, why weren't they insured? If the buyer (friend or otherwise) opts out of insurance, then it's not the shippers issue regardless of friend or customer. But if the shipper sends stuff uninsured because THEY choose to, then I think it's their issue again regardless of friend or customer.
Friend or otherwise, I would always ask if the buyer wants the shipment insured and make it clear that if it's not, and something happens, it's not the sellers fault. That's why insurance is there.

As a friend of many hobby store owners, I never expect (or really never ask for a special price) so when I am given one I am always very grateful, but I do always request for insured shipping if it's not something I can pick up myself.
As far as I'm concerned, UNLESS you requested to not insure the shipment, the seller (again, regardless of if you're friends or not) should be liable. As a business owner, he should automatically send insured and charge for it unless asked otherwise, it's the only way to avoid these issues.
Just my opinion.