Cool. You said:
"Writing a show is a particular skill that begins with creative brainstorming among fellow writers, and then is completed by a single writer who turns ideas into a concrete script. Obviously multiple writers can be involved in a show, but each writes their own part. Writers do not work with figurehead hosts whispering in their ear. PK is not qualified to write a show, plus he wasn't even available while it was being written."
In my professional experience scripts have been written, developed and performed in many different ways that don't follow that template. Often the performer is whispering in my ear during the writing process.
In this case, Patrick Dussault wrote the Gala's "Letter to Bergevin" skit (performed by Peter Keleghan), and, in collaboration with PK, the monologue. In Dussault's own words, "Our idea was catharsis through laughter. I wrote a few jokes that PK said 'no, we can't do that'. To us it was a cheeky way of dealing with a difficult situation with playful jabs."
PK is not a talking head.
Dussault interview:
http://www.tsn.ca/radio/montreal-690/pat-dussault-pk-subban-was-amazing-to-work-with-1.536730