Which prophet told Jeroboam's disguised wife that her son would die?

Answer: Ahijah

Though nearly blind, Ahijah recognized Jeroboam's disguised wife and said the boy would die when she entered the city.

“But the LORD had said to Ahijah, “Behold, the wife of Jeroboam is coming to ask you about her son, for he is ill. You are to say such and such to her, because when she arrives, she will be disguised.””— 1 Kings 14:5 (BSB)