yes, quality of life is a very difficult thing to measure objectively, because of the subjective component, as you state. are you under the impression the "reviews by independent experts" mentioned in the comment above the one you cited would only be meaningful if the person narrating their subjective experience was found to be outright lying? you are clearly familiar with some of the nuances, thus i'm not sure why you would not also be interested in independent reviews of the subject. his personal story is worth a lot, but it's not everything. i would think the more people reviewing it seriously, the more benefit to people like your father (and countless others)