Actually you're right ... with regards to his wife.
On the other hand, trying to establish a pattern of behaviour for purposes of convicting someone of FELONY RAPE against the allegations of a druge taking, suicide attempting bimbo is another story.
Do you really want to go down that road?
BTW, the "drugs", from what I had read, were over-the-counter sleep medicine that she overdosed. Although I am not naive about what goes on in the Colorado mountains around posh ski resorts. I don't doubt harder and illegal drugs were available to her if she wanted them.
If she had a history of "drug abuse", as you say, it might be relevant to her mental competency. Certainly, a lot of the crap that gets abused does have longterm negative affects on the user's mental functions.
I'd just like to hear the drug legalization crowd in here support your premise that prior drug use disqualifies you as a reliable witness in a court of law.