To discover the fate of Menelaus after the end of the Trojan War, we need to look at Book 4 of this epic classic. In this section of the story Menelaus tells Telemachus how he managed to make it home. He, like other Greeks, found that his journey homeward was protracted due to the way that his ship was blown off course. Menelaus found himself stranded in Egypt and is told by Proteus how he can get back to his home.
As for his brother, Agamemnon, the story is somewhat different and much more tragic. Ater a voyage that was marked with storms and tempests, Agamemnon was blown off course and landed in the country of Aegisthus, whom Clytemnestra (Agamemnon's wife) had taken as a lover. Agamemnon's return resulted in his slaughter at the hands of his wife or at the hands of her lover, depending on which account you look at.