The Right To Die is an often ignored but important law for the exact reasons you listed. It's something you don't think you need until you absolutely do need it.

These Frontline Documentaries are very explanatory for those who want to know more :

http://www.pbs.org/wgbh/frontline/film/suicide-plan/

https://www.pbs.org/wgbh/pages/frontline/suicidetourist/

http://www.pbs.org/wgbh/pages/frontline/facing-death/

http://www.pbs.org/wgbh/frontline/film/being-mortal/