Questions about how to use Columbo questions with someone who is nonreligious but “spiritual,” what to say to someone who “followed Jesus out of the church” and now doesn’t believe spiritual truth is knowable, and how to respond to health and wealth preaching.

How would you use Columbo questions with someone who isn’t religious but believes in divine power and describes his closeness to that power as “spiritual”? 

What should I say to my sister who “followed Jesus out of the church” and now calls herself a “spiritual agnostic” and doesn’t believe spiritual truth is knowable?

How should I proceed with a friend who has gotten into health and wealth preaching?