I used to think the question was unanswerable and I didnt think Cal had much influence on Bro at all.
I don’t think Dirk really demonstrates his proclivities, but AR certainly does, and is a good example of what Dirk is like when isolated and unable to connect to his friends,
so I thought the isolation and self-destruction was enough to explain Bro’s descent.
Then @jadedresearcher pointed out something kind of obvious:
Dirk has no interest in SAW, like Bro exhibits. SAW has always been Caliborn’s thing.
So I think Cal’s influence was substantial. Finding out the specifics about that is part of what I’m interested in seeing in Hauntswitch, assuming Bro shows up.