Is the money the husband gets from not staying in the hotel and getting its value back from the company considered unlawful money, knowing that the company might prevent the stay if it knows he can return, and that he only did that once?

To determine the ruling, one must consider the conditions of the company. If the value of the hotel stay was given to him unconditionally, then there is no harm in him keeping it. However, if the payment for the stay was given to him on the condition that he spend the night there, it is not permissible for him to take the money for himself since he did not spend the night, based on the words of Allah Almighty: "O you who have believed, fulfill [your] contracts," and the words of the Prophet, peace be upon him: "Muslims are bound by their conditions." If it is not permissible for him to take the money, he must return it to the company by any suitable means. If he is unable to return it, he should donate it to public welfare and charitable causes.