Why does the ruling on prompting a disbeliever to utter the Shahada at the time of death — that it is permissible to prompt him, and obligatory if his conversion to Islam is hoped for — differ from the case of Pharaoh's conversion to Islam at the moment of drowning, which was not accepted from him?

The statement by Al-Jamal: "Even if we do not apply the rulings pertaining to Muslims to him at that time" means that a dying disbeliever who has reached the gurgling stage is not treated as a Muslim in this world (i.e., no funeral prayer is offered for him, nor is he buried in Muslim cemeteries); rather, he retains the status of a disbeliever. As for his ruling with Allah in the Afterlife, it is unknown due to the possibility of him uttering the Shahadah moments before the gurgling. Therefore, he is prompted to say the two Shahadahs, in case he might benefit from them.