i feel like this is extra fucked up, because:
in "normal" time dilation adventures, you are aging more slowly as the close-to-lightspeed traveler, meaning you have two ages: your experienced one and the calendar-based age from the perspective of the place where you started your journey.
but grace was put into a coma for one of his near-lightspeed journeys, meaning he didn't really experience the time at all, leading to him having three ages.
But ALSO ALSO, at the end of the book, he is living on a planet that has harsher conditions than earth, while recovering from several maladies. While it is not technically affecting his age like the other two factors (coma, relativistic travel), it could be argued that he has four ages, since his biological experienced age also doesn't line up with the usual projections for a man of his biological age.