What is the ruling regarding someone for whom atonement for unintentional killing became obligatory, but who is unable to fast, and is unable to communicate with a person who claimed to have freed a slave on their behalf with this intention?

The expiation for unintentional killing is the freeing of a slave. If the killer does not find a slave, then he must fast for two consecutive months. If he is unable to fast, then, according to the majority of scholars, nothing else is required of him. If it becomes possible to find a slave to free, or to fast later, then that becomes obligatory, provided that a slave has not already been freed.