"Lost Life"

A few days ago, my cousin asked me to make a sketch for her. It's meant to be for an school assignment. So i took my grandfather's picture and tried to draw him. It was a picture from the time when he was still healthy. Yet i didn't make to draw him as he was in that picture. I draw him as i remember him from his last days, when cancer had already ravaged him. His skin is pale, his cheeks are hanging and his eyes have lost the spark they used to have...
The assignment was meant to be called "Lost Youth". The butterfly is a symbol for the flame of youth and the old man is grieving for what he've lost. Yet, looking at the picture i made, I can not think of a lost youth but of a lost life. A life that slipped through this man's fingers and he wasn't able to do a thing to keep it...