Should he retire?

Some, most recently some in Switzerland (where the Holy Father is visiting soon), have said that the Pope should be required to retire at 75, as every other bishop must.

Personally, I do not favor mandatory retirement ages if there are structures and processes are in place to help make up for the deficiencies that come with advancing age and so protect the common good as well as the dignity of the individual.

The Roman Curia has no shortage of such structures and processes.

:-)