Shouldn't this be with "sine" as in His children, not some other guy's children (hans)
No: "De tager sine børn fra ham" would mean, "They take their (own) children from him."
I mean, technically, but usually when you would say something is going to take place in the future you add a few extra words for context.
Maybe no drama is implied in this phrase, though it does give me the impression. Undskyld for ikke at kunne sige dette på dansk :)