We know that Joseph can interpret dreams. The chief butler knows that Joseph can interpret dreams, he just forgot about helping him out after being restored to his position in Pharaoh’s house. Then after Pharaoh has troubling dreams, that his wise men and magicians are no help with, the chief Butler is like “Oh yeah, now I remember…”

Genesis 41 

At the end of two full years, Pharaoh had a dream: and, behold, he stood by the river.

2 Seven well-fed cows came up out of the river; and they grazed in a meadow.

3 Seven other cows came up out of the river after them, sickly and thin, and stood by the other cows on the brink of the river.

4 And the sick and thin cows ate up the seven well fed and fat cows. Then Pharoah woke up.

5 He went back to sleep and dreamed the second time: there were seven heads of grain growing on one stalk, healthy and good. 

6 Then seven thin heads blasted with the east wind sprung up after them.

7 And the seven thin heads of grain devoured the seven plump and full heads. And Pharaoh woke up and realized it was a dream. 

8 In the morning his spirit was troubled. He sent for all the magicians and wise men of Egypt and Pharaoh told them his dream; but there was none who could interpret them for  Pharaoh.

9 Then the chief butler spoke to Pharaoh, saying “I remember my faults today.

10 Pharaoh was angry with his servants, and put me and the chief baker in custody in the captain of the guard’s house. 

11 And we had a dream in one night; each man according to the interpretation of his dream.

12 There was a young man there with us, n Hebrew, servant to the captain of the guard; and we told him and he interpreted our dreams for us; he interpreted to each man according to his dream. 

13 As he interpreted to us, so it was; I was restored to my office and was hanged.

14 Then Pharaoh sent for Joseph, and they brought him out of the dungeon quickly: and he shaved, changed his clothes, and came before Pharaoh.

15 Pharaoh said to Joseph “I have dreamed a dream, and there is none that can interpret it: and I have heard said of you, that you can understand a dream and interpret it.”

16 Joseph answered Pharaoh “It is not in me: God shall give Pharaoh an answer of peace.”

17 Pharaoh said to Joseph “In my dream, I stood upon the bank of the river.

18 And seven cows, well fed and plump, came up out of the river, and they fed in a meadow:

19 And seven other cows came up after them, poor and sickly and thin, such as I never saw in all the land of Egypt; 

20 The thin sickly looking cows ate up the first seven fat cows.

21 And when they had eaten them up, you would never know that they had eaten; but they were still ill looking, as they had been to start with. Then I woke up.

22 I also saw in my dream seven ears of grain come up in one stalk, full and good:

23 And, behold, seven ears, withered, thin, and blasted with the east wind, sprung up after them:

24 The thin ears devoured the seven good ears: and I told this to the magicians, but there was none that could explain it to me.”

25 Joseph said to Pharaoh “The dream of Pharaoh is one: God has shown Pharaoh what he is about to do.

26 The seven good cows are seven years; and the seven good ears are seven years: the dream is one.

27 The seven thin and sickly cows that came up after them are seven years; and the seven empty ears blasted with the east wind shall be seven years of famine.

28 It is just as I have said to Pharaoh: What God has shown PHaraoh what he is about to do.

29 Seven years of great abundance shall come throughout all the land of Egypt. 

30 Then after them seven years of famine; and all the abundance will be forgotten in the land of Egypt, and the famine shall consume the land.

31 The abundance will be unknown in the land because of the famine that follows, for it shall be very grievous.

32 And for that the dream was given to Pharaoh twice; it is because the thing is established by God, and God will soon bring it about.

33 So now let Pharaoh find a man discerning and wise, and set him over the land of Egypt.

34 Let Pharaoh do this, and let him appoint officers over the land, and take up the fifth part of the land of Egypt in the seven abundant years. 

35 Let them gather all the food of those good years that come, and store up grain under the hand of Pharaoh, and let them keep food in the cities.

36 That food shall be stored up for the land against the seven years of famine, which shall be in the land of Egypt; that the land does not perish during the famine.”

37 The thing seemed good in Pharoah’s eyes, and in the eyes of all his servants.

38 And Pharaoh said to his servants “Can we find such a one as this, a man in whom is the Spirit of God?”

39 Pharaoh said to Joseph “Since God has shown you all this, there is none so discerning and wise as you are. 

40 You will be over my house, and according to your word shall all my people be ruled: only in the throne will I be greater than you.”

41 And Pharaoh said to Joseph “See, I have set you over all the land of Egypt.”

42 Pharaoh took off his ring from his hand, and put it on Joseph’s hand, and dressed him in  fine linen garments, and put a gold chain around his neck. 

43 He made him ride in the second chariot which he had; and they cried before him “Bow the knee!” And he made him ruler over all the land of Egypt.

44 Pharaoh said to Joseph “I am Pharaoh, but without your word  shall no man lift hand or foot in all the land of Egypt.”

45 Pharaoh called Joseph’s name Zaphenath-Paneah; and he gave him Asenath the daughter of Potipherah, priest of On, as a wife. And Joseph traveled throughout the land of Egypt.

46 Joseph was thirty years old when he stood before Pharaoh king of Egypt. And Joseph went out from the presence of Pharaoh, and went throughout all the land of Egypt.

47 In the seven abundant years the earth yielded by handfuls.

48 And he gathered up all the food of the seven years, which were in the land of Egypt, and stored up the food in the cities: the food of the field, which was around about every city, he stored up in that city.

49 Joseph gathered grain as the sand of the sea, very much, until he quit counting because it could not be measured. 

50 To Joseph were born two sons before the years of famine came, which Asenath the daughter of Potipherah priest of On bore unto him.

51 Joseph called the name of the firstborn Manasseh: “For God,” he said, “has made me forget all my toil, and all my father’s house.” 

52 And the name of the second called he Ephraim: “For God hath caused me to be fruitful in the land of my affliction.” 

53 The seven years of abundance in the land of Egypt ended.

54 And the seven years of famine began, as Joseph had said: and the famine was in all lands, but in all the land of Egypt there was bread.

55 When all the land of Egypt was famished, the people cried to Pharaoh for bread: and Pharaoh said to all the Egyptians “Go to Joseph and do what he says.”

56 The famine was over all the face of the earth. Joseph opened all the storehouses, and sold to the Egyptians; and the famine was severe in the land of Egypt.

57 And all countries came to Egypt to Joseph to buy grain; because the famine was so great in all lands.