Complex sentence: Although he was reunited with his family in Israel, he did not re-emigrate to the US, contrary to his declaration, and he received Israeli citizenship although he and his family shortly thereafter moved to another western country.
Split into simpler sentences: Although he was reunited with his family in Israel, he did not re-emigrate to the US, contrary to his declaration, and he received Israeli citizenship. He and his family shortly thereafter moved to another western country.