Please explain "for half his flock were in their beds," in W.B.Yeats' poem "The Ballad of Father Gilligan."

In the Bible the Priest is often referred to
as a shepherd and his parishioners as his flock. Jesus Himself is
referred to as 'The Good Shepherd.' So, Father Gilligan is equated with a shepherd who
tends his parishioners who are his flock.

W.B.Yeats' "The
"Ballad of Father Gilligan" is a moving story of how God comes to the rescue of a
sincere priest whose only concern is the salvation of the souls of his
impoverished parishioners.

Father Gilligan who was
exhausted in fulfilling his priestly duties day and night during an epidemic in the
Irish countryside, either in giving the last communion to his poor parishioners who were
dying in large numbers or conducting funeral services for them,  was at home
one evening taking a well deserved
rest and had dozed off in his chair.

Half the population of
the village was already dead and buried because of the epidemic and the other half  was
waiting to die and they were  lying in their sick beds.