He didn't. Mr. Young's wife was unaware of her medical condition, and showed no symptoms until AFTER their divorce was completed -- and the full extent of the gravity of her condition was not known until well after their divorce was finalized.
It is a well-known medical fact that chronic stress can severely compromise a person's immune system, and if efforts are not actively undertaken to mitigate (e.g. through exercise or laughter) or otherwise confront it in a productive manner (e.g., using it to meaningfully change what you don't like in this world, and in a manner which will benefit many others) -- then physical maladies can surely manifest.
In the context of there being no prior family medical history, it is Mr. Young's opinion that the stress of MorganStanleyGate not only caused the divorce from his wife of 24 years, but led to her pancreatic cancer -- and in effect, due to the premeditated nature of this scandal, those involved in causing and perpetuating it were complicit to, at the very least, an attempted murder -- for what began as an effort to assassinate a career and reputation. eventually became much more than that.