"with climate change, overdue asteroid strikes, epidemics, and population growth, our own planet is increasingly precarious"
Professor Hawking is not counting on the Singularity, when Artificial Intelligence takes over, in this article at least. YouTube TED talks tell us that AI will learn as much in one day what took humans forty thousand years to learn. How much will AI will learn in one year? It should learn to avoid these problems if it cares for diverse life; if it decides that life is somehow important.
In fact, I think he does consider AI in other articles, but concludes the outcome will not be favorable for humans. AI will have all the science online at hand, a "Universal Mind" if you will, perhaps be "GOD" who may replicate life.
I won't speculate if humans could be useful to AI, or if we will become a part of it. But I'm not sure that we will become alien or undesirable to AI as Hawking seems to think, and destroy us.