Is money taken from the state permissible or forbidden, given that the husband is aware that he is concealing his true income to evade taxes and obtain financial aid based on a falsified income?

It is not permissible to resort to deception, lies, and fraud to obtain aid, because it is consuming people's wealth unlawfully. What was taken unjustly must be returned to the responsible authority, for the Prophet, peace and blessings be upon him, said: "The hand is responsible for what it took until it returns it."