If Musk goes to Mars he'll die there like anyone else. Organ shrinkage make a return home unlikely if radiation doesnt get you first.
Perhaps the human heart does not really yearn to be free––at least not from gravity. Microgravity affects the heart’s ability to pump blood and provide oxygen to cells throughout the body, which can have serious health consequences, especially upon landing on a planet.
In Space, Astronaut Hearts Work Less, Shrink, And Become More Spherical | Science 2.0. The heart becomes more spherical when exposed to long periods of microgravity in space, according to a study of 12 astronauts
The minimum-energy launch windows for a Martian expedition occur at intervals of approximately two years and two months (specifically 780 days, the planet's synodic period with respect to Earth
26 months - 9 month flight = 17 months on Mars + 9 month return flight for a total round trip of 3 years. Significant organ shinkage will occur in that timeframe; current studies are based on just 1 year. Heart may not work well for a return back to Earth making Mars really a 1 way expedition.