Yes, someone else can collect the lost item on your behalf from the organization that found it.
However, iLost recommends informing the organization about this through the item’s chat/claim window. Also, make sure to forward the confirmation email to the person picking up your item. The item number in that email is necessary to retrieve the item.
*Some organizations may request a valid ID. If you are unable to provide one, be sure to inform the organization via the chat/claim window.
By following these steps, you can be confident that your item will be collected.