Menoetius. (1) Son of the Titan IAPETUS and an Oceanid, Clymene or Asia. In the battle of the gods and the Titans, ZEUS smote Menoetius with a thunderbolt and hurled him down to TARTARUS.

Menoetius. (2) Son of Actor and AEGINA, and one of the ARGONAUTS. He was the father of PATROCLUS, and we learn from the Iliad that he lived at Opous in Locris until Patroclus as a child accidentally killed a friend, the son of Amphidamas, in anger over a dice game. Menoetius took Patroclus to his nephew PELEUS' house in Phthia and gave him to be brought up with ACHILLES, who would be Patroclus' life-long comrade. When the young men set out together to the Trojan War, Achilles tried to comfort Menoetius for his son's leaving by saying that he would bring Patroclus back from the war in glory (18.324-8, a 'futile promise' says Homer). Menoetius at that time offered his son advice which defines the relationship of the two comrades (11.786-9): 'My child, Achilles is higher-born than you are, but you are the elder; and yet in strength he is by far the greater. You must speak sound words to him and advise him well and guide him.' Yet it would be Patroclus' advice to his friend that would bring about his own death, and thus Achilles' death too.
Given the above parentage, Menoetius was the half-brother of Achilles' grandfather AEACUS; but a pseudo-Hesiodic fragment makes him the son of Aeacus and thus the brother of Achille's father Peleus, in which case Patroclus and Achilles would have been cousins.

(Jenny March, Classical Mythology [Cassel & Co: London, 1998])