Although I hate to add to your worries, I feel that it's important to add for others who might some day come along: The statistics for those who go with alternatives (at least for most cancers, not certain on leukemia specificly) run around 90% cure rate. Once they've gone the conventional (slash/poison/burn) route, that drops down to around a 40% cure rate w/alternatives. As mentioned above, the cure rate for conventional treatment is right around 3%, when identical standards are applied. (The MIC likes to "cook their books," by counting the folks who die from things like organ failure resulting from their treatments and opportunistic illnesses resulting from their destroying the immune system as "success stories" for statistical purposes...) Still - 40% is better than 3%; so, if the one cousin will listen to you, things aren't totally hopeless.
It IS soooo frustrating, though, when folks are willing to die rather than stand up to a corrupted medical system... A friend of mine's wife died from breast cancer, after refusing to even consider anything that "wasn't approved." He still seems pretty devasted and lost without her; so, it's hard for me to just shrug and chalk it up to "her life / her choice..." The sad reality, though, is that so many people are SO brainwashed that they're virtually incapable of standing up to doctors, even when their life is on the line...
You and your family will be in my prayers.