Should I continue carrying out the deceased's will to donate the trust money he left with me, or should I hand it over to his heirs from among his cousins, or what should I do?

A friend's bequest for charity must be executed if the bequeathed amount is one-third of the estate or less. If it exceeds one-third, then one-third is executed, and the excess depends on the heirs' approval; if they approve it, it is permissible, otherwise, it is returned to his heirs. Failing to execute a will when its conditions are met incurs a great sin, as Allah Almighty says: "So whoever alters it after hearing it, the sin thereof is only upon those who alter it. Indeed, Allah is Hearing and Knowing." The will must be executed, whether it is written or oral, once it is proven.