It's been 60+ years since I read Zane Grey, but for a year or so I read
every book of his I could get my hands on. I can't remember any
specifics re Purple Sage other than the hero suffers from TB (that's how
he gets in Mormon country), and cures by surviving a case of pneumonia.
The passage of his prose posted certainly makes one cringe -- but I
loved his prose style at the time. One of the biggest disappointments of
my childhood was the movie of _Western Union_ -- I had loved the book,
and the movie was so different. (Can't remember either now -- just the
expectation and the letdown.)

Carrol Cox

P.S. In his Ohio frontier books he makes a hero of an actual historical
figure, Lew Wetzel, who I understand was in life a pathological killer.