Can one be reassured about the fate of a father who died after a severe illness that rendered him unable to move or see, and no one was able to ascertain whether he had uttered the Two Testimonies (Shahadatain) before his sudden death, knowing that he had been diligent in his prayers before his illness?

A supplication for a deceased parent reaches them and benefits them, based on the Prophet's (peace be upon him) saying: "When a person dies, all his deeds cease except for three: a continuous charity, knowledge from which benefit is derived, or a righteous child who supplicates for him." Prayer is not waived for the sick as long as they are conscious; they should pray as best as they can. If they are unable, it suffices to perform it with their heart. If the ترك الصلاة (abandonment of prayer) before death was due to a loss of sanity, then there is no sin upon them. However, if it was while they were conscious, then it is not waived. It is recommended to supplicate, seek forgiveness, give charity, and perform good deeds for the deceased. Not uttering the Shahada at the time of death does not necessarily indicate a bad ending, for Allah's mercy is vast.