What is the ruling on a husband, who is a court expert, taking money from those who give it to him among the parties to engineering cases presented before him, while knowing that he will resolve their cases based on the existing evidence without any change in his intention?

The money given by a litigant to a judge or an expert to assist him in his case is considered a forbidden bribe (rishwah) in Islamic law for the recipient, whether the giver is seeking a rightful claim or an unlawful one. This is because the judge or expert receives a salary for his work, and accepting money from them constitutes a bribe and unlawfully consuming wealth. This falls under the hadith (definition): "Gifts to officials are ill-gotten gains (ghulool)." Therefore, it is not permissible for your husband to accept this money, and he must return it and repent to Allah. If he takes it to rule in favor of someone other than the rightful party, the sin is even greater.