1. Will the deeds of one who dies seeking the truth in religion and increasing his certainty be nullified, and will he enter Hellfire? 2. Is one sinful for delaying prayer due to successive university lectures?

It is not possible to definitively assert that someone will enter Hellfire or that their deeds will be nullified. A distinction must be made between seeking the truth due to ignorance or doubt, and seeking it to attain certainty and increase faith. Doubt contradicts faith, whereas firm belief, which its possessor seeks to increase, does not contradict it.

A Muslim who falls into doubt that removes them from the fold of Islam, and then seeks the right path, remains in a state of doubt until their doubt is removed. If they die in that state, they are not among the believers. As for a non-Muslim who is seeking the truth, if they die while seeking it before knowing it, their ruling is like that of the people of the fatrah (a period when no prophet was sent), because Allah does not punish anyone except after the establishment of proof against them. Punishment is deserved due to turning away from proof or stubbornness towards it after it has been established. However, the disbelief of ignorance, when there was no possibility of knowing the proof, does not warrant punishment for its possessor until the proof of the messengers is established against them.