When I lived in Japan as a young child my American father always had me watch Full House in English. When we moved to the US when I was in the second grade I didn’t have much of an issue with speaking English. I think the only issues were pronouncing some words like corn and also distinguishing between B sounds and V sounds. Reading and writing was a whole another story though, but I got very lucky with the teachers and school I was in. Anyways, watching English shows, videos, and even listening to music sounds like a good idea for Ryan.
We are living very similarly to you right now and it is very tough. I'm searching for a job in Japan to be with my family, but no luck yet. Thank you for sharing your experiences.