In Maccabees 2: 12:46, Jewish men who had fallen away (embraced pagan gods, etc.) fought to defend the Temple against a non-Jewish army (Greeks), and in doing so they died as martyrs defending the faith.
That was not a promise of forgiveness (nor an indulgence to escape purgatory), and perhaps the pope did not promise such, but this was an offering in the hope that these apparent idolators, who were executed by God for a capital, mortal crime, would find pardon and see the resurrection of the just.
"Then every man saw that this was the cause wherefore they were slain." "they saw before their eyes the things that came to pass for the sins of those that were slain." (2 Maccabees 12:40,42)
for "he was mindful of the resurrection: For if he had not hoped that they that were slain should have risen again, it had been superfluous and vain to pray for the dead." (2 Maccabees 12:43-44)
However, while the Holy Spirit records approx. 200 prayers in Scripture in exampling and teaching how to pray and exhorting the same, there are zero prayers to Heaven anywhere in Scripture addressed to anyone else but God, except by pagans.
And praying for the dead was a latter development among some Jews, flowing from paganism.
...it should come as no surprise that we do find instances, particularly in the domain of popular belief, in which non-Christians prayed for the suffering dead in the other world...
These practices developed around the beginning of the Christian era. They were a phenomenon of the times, particularly noticeable in Egypt, the great meeting ground for peoples and religions. Traveling in Egypt around 50 s.c., Diodorus of Sicily was struck by the funerary customs: "As soon as the casket containing the corpse is placed on the bark, the survivors call upon the infernal gods and beseech them to admit the soul to the place received for pious men. The crowd adds its own cheers, together with pleas that the deceased be allowed to enjoy eternal life in Hades, in the society of the good.
The passage cited earlier from the Second Book of Maccabees, which was composed by an Alexandrian Jew during the half-century preceding Diodorus's journey, should no doubt be seen against this background... It then becomes clear that at the time of Judas Maccabeus--around 170 s.c., a surprisingly innovative period—prayer for the dead was not practiced, but that a century later it was practiced by certain Jews. (The Birth of Purgatory By Jacques Le Goff. pp. 45,46 , transcribed using Free Online OCR - convert scanned PDF and images to Word, JPEG to Word, emp. mine)
Also, as for these Maccabean Jews, a Jewish site tells us that the rededication of the Temple was,
led by Judas Maccabeus, third son of Mattathias the Hasmonean, whose successors established the Hasmonean high priesthood dynasty. But which were not a valid high priesthood due to invalid lineage, (Genesis 49:10) being not of the lineage of David, as the Zadoks were, and their line ended up opening the door to the Roman conquest. Their control ended when Herod eliminated every male in the Hasmonean line. (Though The Herodian Dynasty had Hasmonean blood thru two sons and two daughters. through Mariamne.)
Due to the unpopularity of its founders, Hanukkah itself came to be largely ignored within a few decades after its origins. Then when Rome’s crushing power began to be felt in Palestine, the people recognized in Hanukkah a message of hope that new Maccabees would rise and independence would be restored. - The Hasmonean Dynasty | My Jewish Learning
Good day to you and goodbye. As I have told you before, I have not interest in discussing anything with you.