If you have a current Verizon rate plan, the answer is yes. You can tell if your plan is current by its title. If it says "nationwide" in the title, it covers anywhere that your phone works in Hawaii. You can go to verizonwireless.com/coverage to see what areas of Hawaii have coverage.
If you have Verizon home phone service you would have to check and make sure you have a Freedom Plan. It could be Freedom Value, Freedom Essentials, Freedom Extra to name a few but it must say Freedom to include Hawaii and Alaska.
If you have Fios Digital Voice you automatically have all US, US Territories and Canada.
Any Verizon nationwide plan includes all fifty states (including Alaska and Hawaii) if your friend doesn't have it maybe they have an old local plan or perhaps they are not properly educated about the features included in their pan options.