What does "religious mutt" mean?
Mutt is a dog that doesn't belong to any particular breed.
When we use it rhetorically, does it mean something positive or negative?

As coach, humanist, and 'religious mutt, ' Morrie gives his former student a crash course on living.

Question

What does "religious mutt" mean?
Mutt is a dog that doesn't belong to any particular breed. 
When we use it rhetorically, does it mean something positive or negative?

As coach, humanist, and 'religious mutt, ' Morrie gives his former student a crash course on living.

Answer

This makes no sense. Are you sure the word is "mutt" and not "nut"?

Answer

I think it means that he draws upon many religions and not just one, like a mixed breed dog or "mutt".