Why is repentance not beneficial at the gurgle (death rattle), whereas the Prophet (peace be upon him) prayed for his uncle Abu Talib at the time of his death?

If a servant repents or believes before the throes of death (gurgling), his repentance and faith are accepted. But once the throes of death begin, it is not accepted from him. The proof for this is Allah's saying: ﴿And repentance is not for those who do evil deeds until, when death approaches one of them, he says, 'Indeed, I have repented now.'﴾ [An-Nisa: 18]. Similarly, repentance and faith are not accepted when the sun rises from the west, nor upon witnessing the torment. The reason for non-acceptance during gurgling is the cessation of accountability, as the person in this state is overwhelmed in mind and soul, and thus cannot comprehend repentance. Repentance is accepted during a state of accountability and choice, as in the story of the Jewish boy who embraced Islam before his death, and the Prophet's (peace be upon him) call to his uncle Abu Talib, where his faith would have benefited him had he believed. As for the moment the soul departs, the faith of one who had not believed before is not valid, and everyone remains upon what they were of faith or disbelief before the gurgling.