Short answers, pulled from the story.
Shah Jahan II, born Mirza Rafi-ud-Daulah, was the twelfth Mughal emperor and ruled from the 6th of June 1719 until his death on the 17th of September 1719. He was the second son of Rafi-ush-Shan and a grandson of Emperor Bahadur Shah.
Shah Jahan II was chosen by the Sayyid brothers, a pair of powerful nobles who controlled the Mughal throne in 1719. He served as a figurehead; without one of the Sayyid brothers present, he was not allowed to meet any noble or attend the jummah.
Shah Jahan II died from tuberculosis on the 17th of September 1719 at Bidyapur. He had been physically and mentally unfit to rule throughout his reign, suffering from the same disease that killed his younger brother Rafi ud-Darajat before him.
Shah Jahan II was buried beside his younger brother Rafi ud-Darajat at the dargah of Qutbuddin Bakhtiar Kaki at Mehrauli in Delhi.
The historian William Irvine disputed this claim, made by Muhammad Hadi Kamwar Khan, arguing that the emperor's fatal illness was caused by opium withdrawal. Irvine also noted that Kamwar Khan had personal grievances and that the Sayyids had nothing to gain from Shah Jahan II's death.
Shah Jahan II was succeeded by Muhammad Shah, who went on to have a significantly longer reign than the brief reigns of the figurehead emperors the Sayyid brothers had placed before him.