Did the Prophet Muhammad's mother die a polytheist, and what religion should one have believed in during the Pre-Islamic Era (Jahiliyyah) for correct belief?

What the Shaykh said is correct; the Prophet, peace and blessings be upon him, was denied intercession for his mother. As for the religion that the people of the fatrah should have believed in, it was the call of Abraham and other prophets, and some scholars are of the opinion that the message reached them in their own languages. Scholars differed on whether the people of the fatrah are held accountable for the principle of Tawhid (monotheism) or not, while agreeing that they are not held accountable for the subsidiary rulings.