Simon was one of Jesus' four brothers, sons of Joseph and Mary. He is mentioned together with his brothers James, Joses, and Judas in the Gospels, where it appears that Jesus' family initially did not believe in him as the Messiah.
When Jesus taught in the synagogue of his hometown, the people asked if this was not the carpenter's son, and mentioned his brothers James, Joseph, Simon, and Judas.
3Isn't this the carpenter, the son of Mary, the brother of James and Joses and Judas and Simon? And aren't his sisters here with us?" And they took offense at him.
After Jesus' ascension, his brothers were gathered in prayer with the apostles and other believers in Jerusalem, indicating that they had come to faith.