Is it? It's a complementary opinion, but a rather obvious one. I think the main reason why a reader may just dismiss that point of view is that the article simply doesn't give enough information about that (the relation with his parents, or the rest of his life in general), so thinking about it the way the comment presents it is just unsettling and in no way revealing. The article gives you the information to connect with the touching aspect of the story, and I don't feel like there's enough info to understand anything else of it.
I don't think the opinion expressed in that comment is as obvious or valueless as you say.
The article successfully manipulated me to only consider the heart-warming side of the situation, even though I have a disability myself (albeit a milder one, visual impairment with no impact on life expectancy). As I was growing up, the need to be independent was repeatedly emphasized to me. If the commenter's complementary opinion wasn't obvious to me, I expect it would be even less obvious to many readers.
Now, consider the negative consequences of a widely read article like this one for future people with that kind of disability. Will their parents or other involved adults even think about encouraging them to pursue a job or independence? I think not. That's why a comment like the one I pointed out here needs broader exposure.
https://news.ycombinator.com/item?id=19104044