Babies with leukimia?

we just recently found out my 4 month old baby cousin has leukemia. the hospital that he is at says he has about a 50% chance of survival. everyone is devastated, and being a mom of a 7 month old i cant even begin to imagine what his mommy is going through. im just wondering if anyone knows what the treatment process is for babies (the dr said he might need a full blood transfusion and a bone marrow transplant.) and what the survival rate is. other people in our family have had cancer but one was lung cancer and one was a brain tumor so i don't know if its hereditary. any answers and prairs will be soo appreciated. thank you so much.