I don't know much about DMSO, but there are so many alternative treatments that do work. Your little boy can be healed.
I don't mean to intrude but I can't help but to tell you about 2 doctors I found. You're probably bombarded with so much info you don't know which way to go for sure...and you probably have a good doctor but you might want to check these two out on the internet as well...maybe make a phone call .
Dr Burzynski in Texas has a treatment called Antineoplastons but the FDA will not allow him to use it unless the patient has first undergone conventional. Before they started regulating this doctor he was curing more brain cancer than anyone. They might have a way of getting around this...I don't know.
http://www.burzynskiclinic.com/
Also...there is Dr Hanoch Talmor, MD in Gainesville Florida. He is a pediatric specialist who uses alternative treatments to boost the immune system. He works with adults as well. I spoke to him yesterday about my sister's breast cancer. He uses a therapy called biosyntonie along with a wide assortment of alternative methods, including vitamin IV. You might ask him about DMSO. He attributes cancer to our toxic environment and has written a book, not so much about disease, but the power of positive thinking.
http://www.betterw.com/