Explorer Academy Double Helix (book 3)
The adventure continues for Cruz, Emmett, Sailor, and Bryndis as they continue their studies at sea and travel to exotic locations around the world. A mysterious person alerts Cruz to impending danger while he and a few trusted pals explore ancient ruins in Petra, Jordan, and search for another piece of the puzzle his mother left behind. Worst of all, now his father has gone missing, which prompts Aunt Marisol, his number one protector, to leave the ship in search of him.
My mom enjoyed Book #3 as well, she says that there is brief mention of Halloween pp. 24-28, birthdays pp. 203, 207, and evolution p. 213