Is my friend obligated to repay the money that his wife took from him to invest in a clothing factory, which later turned out that the partners of the factory had defrauded them, and is fraud considered like a loss in trade, so the money is not guaranteed?

"The agent in a Mudarabah (profit-sharing) contract does not guarantee the capital unless there is an a'd-dī (transgression) or tafrīt (negligence). Any condition of guarantee is void. If the Mudarib (agent) gives the capital to another person without the permission of the capital owner, or partners with another person using it, then the Mudarib guarantees the capital, as this is considered a transgression. Based on this, the wife's sister guarantees the capital because she did not inform them of the existence of partners, and the husband does not guarantee it unless he guarantees the transgression."