Isn't leukemia also an auto-immune disease? My first thought would be to build up the immune system with LOTS of Vit.C, and other immune boosters, which would also help the whole body. My brother had leukemia as a small child, and while he was treated with chemo and the whole medical route, he made it through, went into remission and has been cancer-free for almost 15 years. My parents found a naturopath dr. after he was "cured' who gave him a whole bunch of herbal supplements to detox his system from all the treatments he received. Echinacea/goldenseal was a big one I remember, along with others, and we also all started taking garlic regularly. I know you're looking for more treatment options, but if you have to go the typical way, it's good to know you can help yourself at the end.
May God's healing hand be on Ryan! It's a devastating change in life, but God's grace is sufficient.