If it's not done you can watch all detective Dee (there are three movies)
https://mydramalist.com/862-detective-dee-and-the-mystery-of-the-phantom-flame
https://mydramalist.com/6659-young-detective-dee-rise-of-the-sea-dragon
https://mydramalist.com/22093-detective-dee-the-four-heavenly-kings
You can also watch some other movies by Tsui Hark, some of them have magic with martial arts, like :
https://mydramalist.com/6676-zu-warriors-from-the-magic-mountain
https://mydramalist.com/3643-a-chinese-ghost-story
https://mydramalist.com/828-once-upon-a-time-in-china (adventure, martial arts)
But I watched them a long time ago, so I don't remember if there is too much horror for a young boy.