If absolutely nothing can be done, then why did Christ go and preach to those in Hades, and how did they get delivered?
Septuagint Psalm 6.5: "For in death no man remembers thee: and who will give thee thanks in Hades?" Anamnesis (remembrance) and eucharist are liturgical acts of koinonoia. They would not need the prayers of the Church if they could do it themselves. They benefit from the Liturgy of others giving anamnesis and eucharist on their behalf.
By pure speculation by a devil's advocate:
Can this not be left to the Mercy of God? Jesus (God) had Divine Mercy on those in Hades. It wasn't anything a created man did, but God Himself, recorded as giving His abundant Mercy, even to those who died before His coming.
Metropolitan Hilarion speaks of the Church teaching that with the decent of Christ into Hell
the Liberation of ALL souls held there was accomplished and not just of the Old Testament righteous."The Descent of Christ into Hades in Eastern and Western Theological Traditions"
A lecture delivered at St Mary's Catholic Cathedral, Minneapolis, USA,
on 5 November 2002
by the Russian Orthodox Metropolitan Hilarion (Alfeyev)http://orthodoxeurope.org/page/11/1/5.aspx
[For full article]
The descent of Christ into Hades is one of the most mysterious, enigmatic
and inexplicable events in New Testament history. In today's Christian
world, this event is understood differently. Liberal Western theology
rejects altogether any possibility for speaking of the descent of Christ
into Hades literally, arguing that the scriptural texts on this theme should
be understood metaphorically. The traditional Catholic doctrine insists that
after His death on the cross Christ descended to hell only to deliver the
Old Testament righteous from it. A similar understanding is quite widespread
among Orthodox Christians.
On the other hand, the New Testament speaks of the preaching of Christ in
hell as addressed to the unrepentant sinners: 'For Christ also died for sins
once for all, the righteous for the unrighteous, that he might bring us to
God, being put to death in the flesh but made alive in the spirit; in which
he went and preached to the spirit in prison, who formerly did not obey,
when God's patience waited.However, many Church Fathers and liturgical texts of the Orthodox Church
repeatedly underline that having descended to hell, Christ opened the way to
salvation for all people, not only the Old Testament righteous. The descent
of Christ into Hades is perceived as an event of cosmic significance
involving all people without exception. They also speak about the victory of
Christ over death, the full devastation of hell and that after the descent
of Christ into Hades there was nobody left there except for the devil and
Bishop Hilarion was also guest speaker at the Divine Mercy Congress where his speech was so greatly appreciated that the applause could not be stopped. This is all the more remarkable because it was also applauded by Cardinal Schornberg and yet by Catholic lights the speech contained some notable heresy!!http://thedivinemercy.org/news/story.php?NID=3132
The [Divine Mercy] Congress Catches Fire!Bishop Hilarion Alfeyev: Christ the Conqueror of Hell
Russian Orthodox Bishop: God's Mercy is immeasurable love of the Father
By Dan Valenti (Apr 6, 2008)