Discovering a hidden family is read as uncovering part of your history or identity you did not know. Tradition also links it to feeling there is a side of someone close that you have never been shown.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.