YA Fantasy/Adventure: After an event involving his father, a boy accompanied by an old werewolf go on an adventure.

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Trying to find a book I read between 2012-2018. A boys father either dies or goes missing. At some point later he meets with an old mentor type character who is also a werewolf. The boy’s father saved the werewolf in an incident involving a silver bullet. After that, im not sure what happens as I have multiple books mixed up in my head. The boy may be captured and taken to a carnival type show where he gets in near death incidents involving barracudas and hungry tigers. The main villain may be an extremely powerful family of vampires. Or it may be neither of those. If you have any clue based off of my description, please let me know!