Tragic that it happened. As someone who has had altitude sickness I can sympathize. It is like a severe flu and unless you go down in altitude can get worse leading to death.I normally live at 118' above sea level so high altitude is something I am not used to. On this years hunt we were almost always hunting above 11K and often just below 12K. Our cabin was at around 8800 feet. Since that case years ago I now take the drug Diamox for a couple of days before getting to altitude and a couple of days after. It helps to condition your blood to run on less oxygen. You need a Doctor's prescription to get it and is commonly used by the military for high altitude combat operations..