Is it permissible, in Islamic law, for the plaintiff to demand his friend to repay the value of a guarantee check, or a part of it, after the partnership's capital was destroyed due to the COVID-19 pandemic and a procedural error in the insurance policy, despite the plaintiff being aware of all the details of the incident and the loss incurred by both parties?

Resolving disputes and conflicts is the role of the judiciary, as it hears from all parties to the dispute and ascertains the truth. A Mufti (definition), on the other hand, hears from only one party and therefore cannot issue an accurate ruling. The hand of the Mudarib (agent in a Mudarabah (definition) contract) over the Mudarabah funds is a hand of trust, so he does not guarantee against loss unless there is negligence or transgression. Proving this is a matter for the judiciary. If liability is established against the Mudarib, the capital owner has the right to demand recompense from him and from his guarantor.