In terms of the process, ultimately it is ministers who make a recommendation to the Governor in Council regarding the length of a term. There are limits in some legislation. In the IRB there is a limit, as I understand it, of seven years for a full-term appointment. You can be reappointed in your position.
I wouldn't be able to speak to the specifics of that individual case, but ultimately it would be a decision made by the GIC on the recommendation of the minister.