Is the expatriate husband obligated to send money to his well-off father, knowing that his salary is low and he has financial commitments and debts, in addition to his wife's disobedience regarding saving and his father's interference in his life?

The obligatory maintenance for the wife is an adequate amount for food, housing, and clothing. The husband is permitted to save from his money as long as he spends reasonably. A righteous wife should not be divorced due to disagreement over the amount of maintenance. The questioner is not obligated to spend on his wealthy father, and there is no harm in him living separately. However, he must honor and be dutiful to his parents, and strive to do so in a way that does not harm himself, his wife, and his children.