Genesis 11:32

And the days of Terah were two hundred and five years. And Terah died in Haran.

AND TERAH DIED IN HARAN. After Abram had left [Haran, as related in the next chapter, and had come to the land of Canaan], Terah remained alive for many years after that. Why then does Scripture mention the death of Terah before the departure of Abram? [The answer is that Scripture does so] in order that this matter [of leaving his home during his father’s lifetime] might not become publicized to all, lest people say that Abram did not show a son’s respect to his father and mother as he left his father in his old age and went his way. That is why Scripture speaks of Terah as dead. Moreover, for the wicked, even while alive, are called dead. Thus the words of Rashi which are found in Bereshith Rabbah.
But I wonder about their words for this is the customary way for Scripture to relate the life of a father, his begetting a son, and his death, and afterwards to begin the narration of the son in all generations. This is the usual manner of Scripture. Noah himself lived yet in the days of Abraham, and his son Shem lived thoughout Abraham’s life span. Now it is possible that the Rabbis came to conclusion of this Midrash because with respect to Terah, Scripture departed from the format of the entire chapter. Regarding Shem and his descendants, Scripture did not mention their death at all, nor did it total the sum of their years. But here with Terah it again follows the first order it used concerning the longevity of the people from Adam to Noah and totals up all the days of Terah and mentions his death. In addition, it mentions the place of death as having been in Haran, the same place it had mentioned concerning Abraham, [i.e., that he had gone there, in Verse 31]. That is why the Rabbis expounded that all this was to make it easily apparent that Abraham was there with Terah when he died. Moreover, because Scripture had already begun the subject of Abraham and told how he had gone forth with his father from Ur of the Chaldees to go into the land of Canaan, the Rabbis found it difficult to understand why Scripture did not systematically arrange Terah’s life and death, and write it chronologically. [That is why they made the aforementioned interpretation.]
And as for that which the Rabbis also said in Bereshith Rabbah — “First you interpret that the wicked, even while alive, are called dead” — this too I find surprising, for the Sages have already deduced from the verse, “And thou shalt come to thy fathers in peace. [His father was an idolater, and yet G-d informed Abraham that after death he would go to him! Clearly the verse teaches you] that He announced to Abraham that his father would have a portion in the World to Come.” Perhaps the intent of the Rabbis was that Terah repented at the time of death, but he lived all his days in wickedness and therefore was called “dead.” In the words of Rashi: “Scripture teaches you that Terah did repentance at the time of death.” Perhaps it may be that our Sages, of blessed memory, say that Terah has a portion in the World to Come by virtue of his son. And that was the announcement, for Abraham did not know it until he was informed of it at the time G-d told him, And thou shalt come to thy fathers in peace. And so I found in a Midrash: “All kinds of wood were valid for use in the altar fire save only the wood of the olive and the vine,. for since oil and wine were offered upon the altar, the fruits save the trees. And so we find in the case of Abraham that he saved Terah, as it is said, And thou shalt come to thy fathers in peace.”
Lech Lecha

וימת תרח בחרן, he had not made an effort to realise his intention of moving all the way to the land of Canaan as he had set out to do in verse 31. He never even visited his son Avraham in the land of Canaan, never observing with his own eyes what a great name Avraham had made for himself and G’d there. Lot, on the other hand, did the opposite for a while at least, having joined Avraham, kept him company and this is why both he and his offspring benefited from this both immediately, such as when Lot became rich in Egypt, as well as much later when Israel was not allowed to conquer the lands belonging to Lot’s descendants, i.e. Ammon and Moav. (compare Nachmanides on Pinchas 25,18)

ויהיו ימי תרח, Terach lived for 205 years. Seeing that the Torah had told us that he was 70 years old when Avram was born, Avram was 135 years old at the time his father died. According to the report in Seder Olam, Avram buried his father two years before the death of his wife Sarah, a statement that is absolutely correct. We know that Avraham was 137 years old when Sarah died, as he had previously been reported as being 10 years Sarah’s senior. This means that Terach must have died 2 years before his granddaughter Sarah.