Was imam Ali's father Muslim

Answer 1

Most Sunni's say he died without being a Muslim. They even state that Prophet Mohammad (pbuh) said " Oh lord, if your going to put my uncle Abu Talib into hell fire, i am praying to you to put him on the most least level so that he don't suffer a lot of pain" (they say prophet prayed because his beloved uncle Abu Talib died without baring witness that Mohammad (pbuh) was God's indeed messenger and that there is no God but Allah)

And when we look at it on the Shia's view of point, They state that Abu Talib did indeed say the Kalima (bared witness) and in order to still protect the Prophet (pbuh) he had to hide it so that the Quraish doe's not harm him. That's why we get the answer stating that Abu Talib did indeed still protected him till he passed away.

My personal opinion will be choice of Shia's thought of school. As it suits it's context more based to the history.