No. 51  section speaks about "Purgatory",  whose existence many Christians deny

But Jesus himself talks about forgiveness in the next life (Mt 12.32)

Regarding both the saints in Heaven and the "souls in Purgatory",
no.51 pastorally calls for the avoidance of "excesses and defects"
in teaching about the Communion of Saints

Faithfulness to the vision of Vatican 2
means keeping the souls in Purgatory on our radar

e.g.  on the Fridays of Lent,
we can gain a "plenary indulgence" for someone in Purgatory
- by praying the "Prayer before a Crucifix":

Behold, O good and kind Jesus,

I cast myself upon my knees in your sight,

and with the most fervent desire of my soul

I pray and beseech you

to impress upon my heart

lively sentiments of faith, hope and charity,

with true repentance for my sins

and a firm desire of amendment,
while with deep affection and grief of soul

I consider within myself

and mentally contemplate

your five most precious wounds,

having before my eyes that which David,

the prophet, long ago spoke concerning you,

"They have pierced my hands and my feet,

they have numbered all my bones"

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