Our purpose here in this life is to love God and love our neighbour. We also play a part in the salvation of souls. When we offer our sufferings in union with Christ, we are participating in salvation history. These struggles and sufferings are to be brought to the altar every Sunday to offer God the merits of our Lord and our offerings too.
That said, when we are at the bedside of a person who we might feel spent time away from God, we are to still intercede for them in this critical time. Perhaps they are unconscious, no longer able to respond, as far as we can tell. God gave us a formidable weapon, which is the infinite merit of Christ, to stand and intercede for them. Even in the last moments, we can be a soldier fighting for them. This is what the Divine Mercy chaplet is. A weapon.
How does this play out in the invisible that we can’t see? Jesus I trust in You.
Remember the little boy in scripture that gave Jesus a few loaves and fish and Jesus fed the 5 thousand. This is what we believe. The merits of Christ are infinite. We just take that plug and plug it in and know power is there.