I think that if OP finds The Matrix too adult, Ex Machina is even less appropriate.
Her is a good recommendation but I struggle to imagine a 12 year old identifying well with alienated-middle-aged-man-malaise ;) (although I loved Lost in Translation at 14 or so)
Arrival is a great recommendation. I had some quibbles with its science, but it’s good Sci Fi. Then he can introduce him to Ted Chiang’s other writing
Her is a good recommendation but I struggle to imagine a 12 year old identifying well with alienated-middle-aged-man-malaise ;) (although I loved Lost in Translation at 14 or so)
Arrival is a great recommendation. I had some quibbles with its science, but it’s good Sci Fi. Then he can introduce him to Ted Chiang’s other writing