Assalaam walaikum,
In a nutshell...the Shia imam states imam are given knowledge of the unseen. A Shia imam actually knows the number of times a mosquito flaps its wings in a minute.
The brother uses examples from the Quran to refute this. He uses the example of the Prophet Suleiman. Suleiman was unaware of the grandeur of Saba. And he was a prophet of Allah.
Thus the Shia position is wrong.