Is the husband obligated to return to his wife and children who reside in another country, knowing that he works in another city for 20 days and takes a 10-day leave, and his wife cannot move to him, and his family does not care for her, and he views her as someone whose husband is abroad? And is he sinful for that?

If your father stipulated to your husband that he must reside with you and not leave you to work in another country, then this is a valid and binding condition according to the Hanbalis. Consequently, you have the right to annul the marriage if the husband violates this condition. It is well-known among the Hanbalis that fulfilling this condition is desirable (mustahabb) but not obligatory, whereas Shaykh al-Islam Ibn Taymiyyah held that fulfilling such conditions is obligatory. However, if there was no condition, but merely a promise, then there is no blame on the husband for moving, unless he is absent for more than six months, and you have the right to a safe, independent dwelling. It is advised to be patient and maintain a good relationship with your husband, and to assist him in honoring his parents and maintaining ties of kinship.