All of the examples are pulled from medicine, notorious for its lack of experimental rigor. To say that "Science has failed us" implies that either medicine is the the only important science or that all science is equally as sloppy, which is pretty insulting to a scientist in any harder field.
His focus on causation is even more misguided. The very purpose of science is to understand the way the world works; to understand what causes what. To attack the idea of causation is to attack the very idea of science, and in turn all of the advances it's brought about over the past 300 years. Beyond that, we implicitly accept causation in almost every aspect of our lives (Pressing the space bar causes a space to appear, etc). Certainly causes can't be 'seen' like facts, but to suggest that this trivializes them, or somehow makes them less useful is nonsense (and, for what it's worth, is total misreading of Hume).
Complexity isn't a valid reason either. Some very well understood systems are incredibly complex (look at the computer you are using now). What is true is that like all other humans, scientists make mistakes. We often make the incorrect causal links or are influenced by our biases. This is why experiments exist (instead of pure data collection); to make sure the causes we have assumed are correct. To point to a couple of experiments with an unexpected result and then say that all of science has failed isn't even a little bit right.