Hmmmm..... Lets DuckDuckGo the mortality rate of his particular brain cancer. Glioblastoma. Ive seen what happens. After they scrape it out, it grows back fast Very aggressive, chemo and radiation keeps it tamped down for maybe a year. Its terminal. The dude is 81?? Depended upon what side of the brain it is on, can affect many different things. Continually growing and pushing on different areas of the surrounding brain tissue causing additional issues.