Jackie:
The benefits can be worth the risk for a lot of people. I'm on my sixth year of remission, although I can't completely credit Rituxan for that since there is no logical reason for it to last that long. When it works, it can cause about a year of remission on average.
The main risks are side effects during the infusion, which are usually easily controlled with pre-meds. Side effects after the infusion are rare, but they include feeling flu-like for a day or so, serum sickness (which can be a bit more serious, I've had it twice), and PML (which can be very serious and is extremely rare).
My question is though, has he tried anything other than IVIG? No steroids?