Can life advice from a substance abuser or anyone on prescription mood alterers be anything but suspect?

Yes, people are all still just people, regardless of whether they are addicts, or prostitutes or ... well anything other than Trump supporters :P Fact is that an addict might still well be more in touch with reality than someone else... and perhaps still retains a lot more commonsense than most people

Yes, because first-hand experience sometimes makes for a much better cautionary tale than sermons from those who are on the outside looking in. 
~

Sometimes it can be suspect. Example: My sister complaining about me drinking as she sits there with her oxygen pack, smoking a doobie. I do agree with DayDream and Randy.

I think any “life advice” should be weighed carefully, no matter the source.
There is merit in guidance from those who can speak from direct experience, but taking advice at face value may be at your peril. This post was edited by Don Barzini at September 24, 2018 8:04 PM MDT

not sure

We never know where we might find wisdom.