But you aren't saving them from the negative impact, you are only delaying it. In fact, in some instances you are delaying the 'death' impact and adding the negative experience of a long drawn out illness. Unless one of these people close to you die durring the illness process, the net suffering inflicted is no less than equal and potentially greater. Perhaps if you are estranged from your loved ones a long drawn out illness would give you time to get to reconcile and know each other, but other than that I have a hard time seeing the benefit of delaying death for a period of extended illness.
You left out the first half of the sentence "fit to live a normal life". Someone with a debilitating and incurable illness is not living a normal life, from my POV. That was my grandmother for about 5-10 years in her battle with Parkinson's. Eventually she couldn't walk, stand, talk, feed herself, etc. People generally wouldn't call someone in that circumstance selfish for wanting it all to end. That is entirely different from someone who is otherwise healthy, but suffering from treatable depression. That depressed person may also want to kill himself, but that may be considered selfish by a lot more people.
