Is the money obtained through forging medical documents and giving false testimony considered unlawful (haram), and what are the ways to rid oneself of its unlawfulness?

If the state grants money to returnees according to certain conditions, it is not permissible for anyone to defraud in order to take what is not rightfully theirs; for that involves lying, cheating, and unlawfully consuming wealth, and these are forbidden acts. You are obliged to repent to Allah and refrain from taking more than your due. However, if refraining would result in significant harm, then it is permissible for you to take all the money and then dispose of the excess by giving it to the poor and needy or spending it on public welfare.