Is the father's refusal to give his son the money the latter saved for his sisters' marriages and to buy a house considered a sin on the son's part, especially since the father does not spend on the family, spends his money on women, and borrows for his desires?

You must give to your needy father from your wealth, provided it does not harm your own wealth. It is not permissible to assist him in a sin. You are not obligated to repay your father's debts, especially if they were incurred for falsehood. The father is obligated to provide for his wife and his young children who have no wealth.