@TTW
The duration of the torment is not discussed. So there is no supporting proof that the torment is not going to end. It's just assumption that it will or will not end.
However, good news for you. The Pharisees believed the torment would last until the final judgment when the torment would be worse. You know, out of the frying pan, into the fire so-to-speak.
HISTORICAL NOTE: That the view of hell depicted in Luke 16 was an integral part of first century Pharisaic tradition is nowhere more clearly delineated than in the following excerpt attributed to Josephus (himself a Pharisee) to explain the Jewish concept of Hades to the Greeks.
Now as to Hades, wherein the souls of the righteous and unrighteous are detained, it is necessary to speak of it. Hades is a place in the world not regularly finished; a subterraneous region...allotted as a place of custody for souls, in which angels are appointed as guardians to them, who distribute to them temporary punishments, agreeable to everyone's behaviour and manners... while the just shall obtain an incorruptible and never-fading kingdom. These are now indeed confined in Hades, but not in the same place wherein the unjust are confined. For there is one decent into this region...the just are guided to the right hand, and are led with hyms, sung by the angels appointed over that place, unto a region of light, in which the just have dwelt from the beginning of the world; not constrained by necessity, but ever enjoying the prospect of good things they see, and rejoice in the expectation of those new enjoyments which will be peculiar to every one of them, and esteeming those things beyond what we have here; with whom there is no place of toil, no burning heat, no piercing cold, nor any briers there; but the countenance of the Fathers and of the just, which they see always smiles upon them, while they wait for that rest and eternal new life in heaven, which is to succeed this region. This place we call The Bosom of Abraham.
But as to the unjust, they are dragged by force to the left hand by the angels allotted for punishment, no longer going with a good-will, but as prisoners driven by violence... they are struck with a fearful expectation of a future judgment, and in effect punished thereby: and not only so, but where they see the place of the fathers and of the just, even hereby are they punished; for a chaos deep and large is fixed between them; insomuch that a just man that hath compassion upon them cannot be admitted, nor can one that is unjust, if he were bold enough to attempt it, pass over it. (Underscoring mine)
Source: Flavius, Josephus, The Works of Flavius Josephus, William Whiston, A.M., Translator. pp. 901-902