HAve him stick to what his doctor has him doing. Extended release niacin given at 1000 mg for 4 weeks, 1500 mg for 4 weeks, and 2000 mg for 8 weeks (16 weeks total), was shown to increase HDL 26%.
http://archinte.ama-assn.org/cgi/content/full/160/8/1177
Fish oils are great, but it's the EPA and DHA that are the key ingredients to their benefits. Sometimes in dietary supplement fish oils, you may have 1000mg of fish oil (or krill oil) but only 150 mg EPA and 90mg DHA.
Prescription fish oil pills are 1000mg oil, but 465mg EPA and 375mg DHA. They go through multi-step refinement and purification processes and are FDA approved. Fish oil caps are usually only prescribed for very high triglycerides though, not for increasing HDL or lowering LDL (or for CHD patients for cardioprotection).
The problem is, for lowering TG, 4+ grams EPA/DHA are needed, but for cardioprotection, about 1 gram EPA/DHA will do. So...if your krill or fish oil pissl only give you 150mg EPA / 90mg DHA...that's a LOT of pills to swallow, and a LOT of money to spend. Plus, you are not getting an FDA controlled product, so you DO NOT KNOW what has been done to filter out environmental toxins, such as mercury and PCBs (from fish oils). No guarantees on what you're getting in your supplement product. Hate to have to take 10 pills of 1000mg of oil (10,000mg of fish oil)...or worse yet, 30 pills (30,000mg of questionable oil) and not be sure what was done to filter out toxins.
Back to the topic at hand...for your friend, have him stick with the niacin prescribed from his doctor, and stay off the winny. He can talk to his doctor about taking in extra fish oils, etc. for cardioprotection...his doctor will probably be cool with it, but may not have any recommendations.
Also, there are some good fish oil supps out there with high amounts of EPA/DHA in a reasonable dose. I buy mine in liquid form in the refrigerated section of a health food store. It has 900mg EPA and 600mg DHA in one tblsp.
TMI, I know. Sorry.