Hi, Notready
I'm sorry that you both have to face this at such a young age. You have already gotten a lot of great advice for your boyfriend - but I want to add some advice for you. The next few month will be as emotionally distressing for you as him. This site will be supportive, as well as prayer or meditation (or both), wise friends, perhaps a counselor. Remember to be good to yourself so you can help him.
One of the batches of statistics I have looked at showed a strong corrolation between the marital status of married and improved survival. The conclusion of the study indicated that having a spouse (or significant other like you) made it more likely the patient would be able to complete the treatment on protocol - a very important factor in how successful it is.
I am guess that you feel pretty helpless at this point - but I have confidence in you and your ability to help.
Keep posting - we will be rooting you on.
Maria