Is expiation (kaffarah) required for lying about not receiving the dowry forty years ago, and what is the amount of charity (sadaqah) due on behalf of the groom?

The one who denies the dowry is obliged to repent to Allah and return the right to its owner. If it is impossible to reach the owner or their heirs, it is permissible to give it as charity on their behalf. If the dowry is old and the currency value has changed, the most apparent ruling is to return its purchasing power, taking into account the change in value.