My heart goes out to you in your time of grief. I can only imagine how you must be feeling because you, of all people know how our bodies heal themselves if given the chance. I read your story in the link your provided in another thread on this forum, Natural Hygine: The Greatest Health Discovery. What an amazing testimony you have. I'm sorry your friend listened to "medical professionals" instead of you.
Each of us have the free will to make choices and I can tell from all the reading I have been doing on this forum that a lot of people have made the choice to heal their bodies because of you Chris! I hope you can take comfort in that. I understand about your father being from the "old school", its hard to tell elderly people something they have believed all their lives is wrong or that there is a better way.
Just know that you did your part in telling both of them and that was the best you could have done. Again thank you for being here for all of us Chris.