The western world cannot currently accept alternative/complementary therapies as viable treatment. This is mainly due to the fact that all treatments require scientific explanations behind their workings in order to be approved. But just because they are not FDA (or similar organization) approved doesn't mean it doesn't work. However, it's beginning to change. Famous hospitals such as the Mayo Clinic have begun research on some therapies, and so far have had positive results, afaik. In fact, some already approved drugs have natural origins. For example, a cancer drug that I have used was derived from a tree (Topotecan/Hycamtin comes from the happy tree), and Premarin comes from horse urine. Approach them with open hearts and minds, and you might be surprised at the results. That's not to say that all alternative therapies work...but in my experience, some do.
I currently am undergoing treatment for cancer as well. Have been for the last year and a half, since I was pulled out of my sophomore year of college studying biology. I have been employing a blend of eastern and western medicine, and feel pretty great. Have not caught any other illness despite my immunity being quite low 2/3 of the time. I practice some alternative therapies everyday, and feel that it is working.
Some tidbits on my philosophy on cancer (not that you asked for it, nor am I an expert). Read when you (as in you and family) are less angry and shocked:
-Cancer is not necessarily an evil/bad thing, and can disappear suddenly. After all, cancer are rogue cells FROM YOUR OWN BODY. Your own body made these cells, and can eliminate them as well. We all get cancer cells, and usually they are killed off before they propagate into something bigger. Your body has natural defenses against these things.
-Soil is more important than the plant. Your body is the soil on which the cancer grows. If you kill the cancer without changing the body such that it is adverse to cancer growth, the cancer can just grow back. In other words, the cancer is a symptom of a deeper illness. Look to lifestyle, mental, diet, etc. for the real cause.
-Cancer doesn't have to be a bad time in your life. It can bring things that are hard to achieve in a normal, busy life. Take time to enjoy. Among other things, I have received a greater sense of spirituality in my time with cancer.
-Feel more, think less. Many times, I have felt that I had been lead to a decision with a type of confidence that no logic/thought could deliver or justify. It has not steered me wrong yet. I used to be a very analytical and logical person, looking for "the best way" and overthinking things several steps into the future. In this last year and a half, I found my self drifting away from this mental state. I couldn't choose what was "best", because not even the doctors knew what that was. I couldn't predict, because I was so often incorrect due to the erratic nature of cancer treatment.
-Mental state is key. Positive emotion is important. Thinking, "Ugh, I can't do this. I'm sick" or "It hurts, it hurts!" will only perpetuate any pain or illness. The negative vibes will be sent through the body, as it resigns itself to being "sick" or "in pain". However, being proactive about your treatment and approaching it with a positive outlook can do wonders. You've much more power over your body than you think.
That said, I'm not expecting to really convince you and your family of any of these right now. Rather, I'm just planting seeds such that when you experience these revelations for yourself, you are more open to them.
Have a good day.