My uncle too died that way..and yes it was devastating to all of us he left behind, specially his mom. However his brother who died less than a day before him, died an instantaneous death by a heart-attack, and his death was also very painful a blow to all those who loved him. I guess those who love us will suffer to a degree when we die, regardless of how we go.
But I agree somehow a blessed instant death still beats a long suffering one. And I always pray to live and die being dependent on only God alone, and not as a burden to any living soul.