Did one of Noah's sons die in the flood?
Yes
11:42-43
Noah cried unto his son and he was standing aloof - O my son! Come ride with us, and be not with the disbelievers. He said: I shall betake me to some mountain that will save me from the water. (Noah) said: This day there is none that saveth from the commandment of Allah save him on whom He hath had mercy. And the wave came in between them, so he was among the drowned.
No
21:76
And Noah, when he cried of old, We heard his prayer and saved him and his household from the great affliction.
37:75-77
And Noah verily prayed unto Us, and gracious was the Hearer of his prayer. And We saved him and his household from the great distress, And made his seed the survivors.
Yes, one of his sons died in the flood, but he is not considered his son in Allah's eye. The following verses talk about what Noah said after his son was drowned:
11:45 And Noah cried unto his Lord and said: My Lord! Lo! my son is of my household! Surely Thy promise is the truth and Thou are the Most Just of Judges.
11:46 He said: O Noah! Lo! he is not of thy household; lo! he is of evil conduct, so ask not of Me that whereof thou hast no knowledge. I admonish thee lest thou be among the ignorant.
11:47 He said: My Lord! Lo! in Thee do I seek refuge (from the sin) that I should ask of Thee that whereof I have no knowledge. Unless Thou forgive me and have mercy on me I shall be among the lost
