He's spent and made far more than that from industries that spew out the very same kinds of toxic chemicals and radiation that causes people to get sick in the first place. And he fights against pollution controls, he fights against international efforts to manage climate change, he fights against government regulation intended to help preserve a healthy environment and planet for society as whole and for future generations, and he funds right-wing propaganda organizations.
Also... Like Gates, the Koch brothers were born into wealth. He's made more wealth by running and owning businesses that make the rest of us less healthy, then he wants to be painted as a philanthropist -- which is something he can buy, anyone can buy, at that level of wealth. And there are tax reduction incentives to do it. And he's one of the biggest behind-the-scenes manipulators of political discourse in the US, which greatly distorts the public debate, and the actions of Congress, away from carrying out the express wishes of the vast majority, and away from doing what's in the best interest of society as a whole, toward things that favor him, and his kind, personally. He is a force for those who say, "Screw people who are less well off than me, with less talents or abilities or family resources than I had. Every man for himself!" So yes he's both parasitic, and part of an aristocracy, and a net lose for society, despite any "positive" thing he may have done. We don't judge Hitler on the whole based on the fact that he kissed some babies at political rallies, or that he funded national exercise programs for German youth. We judge him based on the full spectrum of things he did, including the very bad things he did, that he chose to do, intentionally, and that hurt others, that hurt large numbers of other people -- that dominates his legacy. That's how I evaluate Koch, and how I think you should as well.