People who died upon shirk (associating partners with Allah) while being ignorant: should we make du'a' (supplication) for them?

The questioner : The common people who recite the Qur'an, or those who are preparing to complete a recitation of the Qur'an, from among our fathers and grandfathers who passed away while holding the belief of making du'a' (supplication) to the dead and the like of that which is prevalent, and they died, and this matter became apparent to us that it is not permissible, so from the perspective of du'a' (supplication), do we make du'a' (supplication) for them or not, given that they did not know what they knew to be the truth, but rather the scholars present with them led them to this matter and told them that this is the religion and there is nothing else?

The Shaykh : As long as they were preserving the pillars of Islam, you make du'a' (supplication) for them, because you do not know what is in their hearts. If it were... well, we are drowning in goodness. May Allah bless you.

The questioner : This is good, secondly.

The Shaykh : A second thing, and I think there is a third thing of goodness...

The questioner : This, O Shaykh, has a good smell, O Shaykh.

The Shaykh : May Allah make you good. May Allah reward you with good.