It is not my place to judge the hearts of others as pathetic or virtuous. I was merely offering a view. It is impossible to know what will be in my or my loved ones heart(s) when/if this time comes for me, or the same if this happened to someone I know. This is one of the most difficult things a person can face and what is in your heart is natural and not invalid. But neither is anyone else's; it is your heart, your innermost fortitude and driving force... not a cold, calculable problem solvable by efficient logic. The 'truth' in your heart or your sister's or your friends or family or anyone else facing your dilemma is equally valid and most importantly borne out of love, not out of foolishness or selfishness. It's probably shallow and unhelpful to say that you may find solace in this shared love, but after your sister is gone this must persist and your heart's convictions and lamentations both will wither.
I am not a very spiritual person. I try to celebrate my life as I can because when the 'lights go out', there may be nothing else. People with M.S. (or any disease) probably feel life's ticking clock pounding in their head more than normal people. My life is precious and (ironically?) I live a bit more cavalierly than others I know. I'm not above trying to sneak into North Korea or running after wild elephants in Tanzania, frantically squeezing every last sweet drop from the fruit of life that I can. I am pretty young. I hear people my age talking about the future, their careers, getting married, having kids, and know that such luxuries are not guaranteed to me. But my life is precious and I want every single millisecond I can get. Do I deserve less because of a disease I did nothing to 'earn'? My heart compels me to live, live, live. Do it now, do it faster; more, more, I say. Will I in the same situation you face? I hope to never know but realize that I may not be so fortunate.
But neither will anyone else, necessarily. Everyone else's clock is ticking as well, albeit perhaps a bit more politely quietly internally. We are probably more sensitive to it and think that our hearts hear echoes of hope that those who do not face such trials cannot possibly detect. But as I said before, neither is right, neither is wrong... certainly neither are inherently foolish. Celebrate life, celebrate love.
Right, now I'm rambling too.