Unsong is a work of online serial fiction by Scott Alexander which is based heavily on Judaism. (I highly recommend it to Jews and Gentiles alike.). As I discussed in my earlier question here, the Talmudic story of Rabbi Elisha ben Abuyah, aka Acher, plays a prominent role. Now the last chapter of Unsong presents a fictionalized account of the aftermath of Acher's death.
[O]ne day Acher died, and the people said that it was not good, because he had never repented, and Rabbi Meir laughed and said that surely had had repented in his heart and was in Paradise. And then flames started coming out of Acher’s grave, and the people were like, we’re not rabbis, and we’re no experts in omens, but that doesn’t seem, to us, like the sort of thing that happens when you’re in Paradise. And Rabbi Meir said very well, but that God would relent and redeem him later. And the people said that, again, we’re no experts and you’re the one with the rabbinical degree, but a voice had very clearly rung forth from the holy places saying that wouldn’t happen. And Rabbi Meir said that very well, maybe He wouldn’t, but if God wouldn’t redeem Acher, then he, Rabbi Meir, would redeem Acher. And the people said, what, that doesn’t even make sense, is redemption not reserved for God alone? And Rabbi Meir said that wasn’t exactly true. That what we do during our lives echoes forward into history, and that good deeds that seemed tiny when they happened might grow and grow until they consumed the entire world, and if the recording angels had discounted them when they first reviewed the case, an appeal might be lodged. And that one day, when he was studying Torah under Rabbi Elisha ben Abuyah, Rabbi Meir had gotten something from him, some tiny spark of goodness, and that was what had inspired him to be good himself throughout his life. And so he would train his disciples to be good, and they would train their disciples to be good, until the world was safe and free, and all of it would be because of this one man, Acher, a wicked wicked man who would not repent, and God would be forced to credit those deeds to Acher’s name, and he would rise into Paradise, unrepentant still. And the people asked, huh, how does that even work? and Rabbi Meir said that this was all playing out on hidden levels, that the point was to redeem the sparks of divinity that had gotten caught among the klipot of the world, and that each of our actions changes and redirects the flow of subtle currents upon which the sparks are borne. And even though Acher had died without repenting, even though everything he did seemed to the material eye to be evil and without merit, behind the scenes the sparks had been pushed into new configurations, whole fiery rivers of sparks, flowing through Rabbi Meir and through all the other people he had touched in his life, and that when all those rivers met and reached the sea, we would get Moschiach, the savior, and the whole world would be reconciled to God. Say not, he told the people, that anything has worked only evil, that any life has been in vain. Say rather that while the visible world festers and decays, somewhere beyond our understanding the groundwork is being laid for Moschiach, and the final victory.
Now as can be seen from this answer, this whole dialogue between Rabbi Meir and the people isn't present in the Talmud, it's just a literary creation. Still, I'm interested in whether the content of what Rabbi Meir says here is based on Jewish beliefs, specifically the part in bold.
My question is, is it true that it's possible to lodge an appeal for a soul that has gone to Gehenom, if the recording angels who made the decision to send the soul there failed to take into account tiny good deeds which later led to enormous good in the world? Or is this whole concept just artistic license?