Here "heart" is a metonym for "mind." The phrase "it came into his heart" is an idiom that means to decide something. Alternate translation: "it came into his mind" or "he decided" (See: [[rc://en/ta/man/jit/figs-metonymy]] and [[rc://en/ta/man/jit/figs-idiom]])
This refers to his people, and not just to his family. Alternate translation: "see how his own people, the children of Israel, were doing" (See: [[rc://en/ta/man/jit/figs-explicit]])