Is the Shaykh correct in refuting the use of Bukhari's hadiths as evidence, in not relying on Sayyid Sabiq's fiqh, in prohibiting the recitation of the Quran at the grave and supplicating for the deceased after burial, and in saying that the deceased is not tormented in their grave but rather their torment is presented to them?

This person is mistaken in denying the validity of using hadiths from Sahih (definition) al-Bukhari as evidence, and in his statement that most of the hadiths in the book Fiqh Al-Sunnah (definition) are weak and unreliable, and in his assertion that the deceased is not tormented in the grave but rather has their torment displayed to them like a television. The book Fiqh Al-Sunnah is beneficial despite containing some weak hadiths, and it is not fair to claim that most of its hadiths are weak.