While not related by blood, their feast day is celebrated together because their remains were brought to Rome at the same time. The Sacred Heart reliquary also has their remains together.
St. Philip Patron: hatmakers and pastry chefs
Quote: Philip said to him, “Come and see.” ~John 1:46
St. James the lesser Patron: pharmacists and the dying
Quote: Little is known of St. James the less (smaller) except that he was called by Jesus to be one of the Apostles and he was present with the other Apostles after the Ascension.
John 1:43–46: The next day he decided to go to Galilee, and he found Philip. And Jesus said to him, “Follow me.” Now Philip was from Bethsaida, the town of Andrew and Peter. Philip found Nathanael and told him, “We have found the one about whom Moses wrote in the law, and also the prophets, Jesus, son of Joseph, from Nazareth.” But Nathanael said to him, “Can anything good come from Nazareth?” Philip said to him, “Come and see.”
John 14:8–14: At the Last Supper, as Jesus was speaking about the Father, Philip said to him, “Master, show us the Father, and that will be enough for us”, to which Jesus gently responded, “Have I been with you for so long a time and you still do not know me, Philip? Whoever has seen me has seen the Father”
Matthew 10:3, Mark 3:18, Luke 6:15: All list James as and Apostle
Acts 1:13: St. James is present after the Ascension of Jesus Christ