There is no law requiring pilots to retire at age 60 in Canada. Up until last year, no one could Captain a transport category aircraft in US airspace beyond age 60. This made it impractical to have pilots over 60 employed next door here in Canada. That FAA rule no longer exists.
The ACPA has negotiated an age 60 retirement for its members. It too is likely a throwback; to when the average 60 year old was unfit to fly. Not so today.
Will they continue with this old school notion, who knows?