A friend of mine was recently diagnosed with primary progressive multiple sclerosis. is this a fatal disease?

Cannot predict: Primary progressive ms is typically without rapid relapses, but also, without remission. Does not seem to respond well to meds employed in relapsing/remitting form. Most active therapy is symptomatic. However, research is ongoing with Gilenya (fingolimod) for ppms. Other drugs not yet on the market are being studied. Best bet is to get into one of these studies. Contact local medical school. Stay positive.