Why are some or perhaps many priests unaware of the APOSTOLIC PARDON?? can the Apostolic Pardon remit all punishment due to sin and what are the conditions necessary to do so??
Concerning your question about priests and their knowledge of the Apostolic Blessing, I cannot answer.
But with regard to whether the Apostolic Blessing is ordered toward remitting all temporal punishment, the answer is yes. The prayer itself makes clear it is ordered toward a plenary indulgence. It reads:
“Through the holy mysteries of our redemption may almighty God release you from all punishments in this life and in the life to come. May he open to you the gates of paradise and welcome you to everlasting joy.”
Notice the words, “release you from all punishments.”
The ordinary conditions for a plenary indulgence would apply if the individual is capable of fulling them:
be in a state of grace
have the interior disposition of complete detachment from sin, even venial sin;
have sacramentally confessed their sins;
receive the Holy Eucharist (it is certainly better to receive it while participating in Holy Mass, but for the indulgence only Holy Communion is required);
pray for the intentions of the Supreme Pontiff
However, the Church has a provision for individuals who are physically unable to satisfy the ordinary conditions for a plenary indulgence, which is understanding given the Apostolic blessing is given in the danger of death.
Note section 2 in the 2006 USCCB’s publication, Manual of Indulgences, No. 12:
At The Point of Death
§1 A priest who administers the sacraments to someone in danger of death should not fail to impart the apostolic blessing to which a plenary indulgence is attached.
§2 If a priest is unavailable, Holy Mother Church benevolently grants to the Christian faithful, who are duly disposed, a plenary indulgence to the acquired at the point of death, provided they have been in the habit of reciting some prayers during their lifetime; in such a case, the Church supplies for the three conditions ordinarily required for a plenary indulgence.
§3 In this latter case, the use of a crucifix or a cross in obtaining the plenary indulgence is commendable.
§4 The faithful can obtain this plenary indulgence at the hour of death, even if they have already acquired a plenary indulgence on that same day.