I am very sorry to hear about your nephew. I hope that he is not in too much pain.
I do not have any information on the flaxseed oil, but I just wanted to mention that you might want to try an energy healer, if you havent already. And I know that not too many people are open to "alternative" modalities of healing, but at this stage there is nothing to loose, and if some reports that I have heard of and seen are true, there might be a life to gain!
I wish you the best of luck with all your efforts to save your nephew's life. Do not give up hope. Godspeed!