Know the carry and hunting laws in your own and any other state you may be carrying/hunting in. There are out-of-state CC permits (FL and UT among others) recognized in multi states, but car carry is even more highly restricted in some states. Laws for carrying when hunting will be covered in the hunting regs book you can get where they sell hunting licenses.
It sure would be nice to have some sort of reciprocity between the states, so as not to have to deal with all of the quirky laws of different states.
Until the perfect world arrives, with the right comes the responsibilty, and in your friend's case it was his responsibilty and nobody elses. Sorry I can't work up much sympathy