I know that's an odd subject for this thread, but Texas beat them to this by almost 10 years.
CPRIT (Cancer Prevention and Research Institute of Texas) was founded in 2007 and chartered with spending $3B over 10 years to develop new approaches to cancer prevention and treatment. If you're in the cancer research space, you know about CPRIT. It's the single largest research fund for cancer outside the NIH.
To get an idea of what $3B can do, check out the CPRIT site http://www.cprit.state.tx.us/a....
If you don't want to do that, basically you can fund a few companies and a number of research projects, but it's nowhere near enough to make a dent in the problem.
There's also the problem of fairly allocating the funds. CPRIT ran into this problem early on when it was found that many of the early, large grants were awarded without proper review to friends of the board. This prompted the entire scientific board to resign and CPRIT to essentially reset. It's moving along OK now, but it's still an open question as to how many of the investments will yield actionable results.
Given Facebook's proclivity to reward friends with purchases at outrageous valuations, I won't be surprised if this fund runs into the same nepotism issues CPRIT did.
There are many other lessons that they can learn from CPRIT, but the most important probably is that $3T is probably a more realistic number.( See also all the comments about the tech industry's hubris when it comes to these types problems - curing cancer/disease is not the same as slapping together some APIs to create a "world changing" app. )