Well, it definitely can be fatal...however, not everyone who has it passes away from it. What level is his pulmonary function? Do they have him on oxygen? What did they think was wrong before they decided on this? My mother had this and it was from numerous blood clots over the years. However, at 83 she still had 50% function - not enough for oxygen but she was on Flovent and albuterol. She passed away from other causes.