Has misguidance truly afflicted someone who unknowingly blasphemed Allah, and is no longer able to repent or perform Salah, while suffering from symptoms of sorcery or demonic possession?

One must not surrender to the whispers that induce a sense of inability to repent and maintain prayer. Instead, one should seek Allah's help, turn away from these whispers, and strive diligently to preserve prayer, while being mindful of the grave danger of abandoning it. As for transgressing against Allah, if it was involuntary due to illness, there is no sin. Otherwise, it is a grave sin that requires sincere repentance with devotion to Allah and earnest supplication. For the door of repentance is open, and Allah's forgiveness is greater than any sin.