What is the ruling regarding someone who dies owing a prayer, in that the muezzin made the call to prayer and he did not perform it for some reason, then died before performing it?

If a man dies and was unable to perform the prayer, then Allah, the Almighty, will not hold him accountable for it. However, if he was able to perform it but fell short until he died, then he will be held accountable for that. Nevertheless, his guardian (wali) should not perform the prayer on his behalf, because prayer is an act of worship in which proxy is not permissible. His guardian should instead increase in seeking forgiveness, supplicating, and giving charity on his behalf.