How sound is the story of Al-Tabarani, Abu Al-Shaykh, and Abu Bakr Al-Manqari complaining of hunger at the grave of the Prophet, peace and blessings be upon him, and a 'Alawi bringing them food by order of the Prophet, peace and blessings be upon him, in a dream?

This story cannot be relied upon to prove rulings or beliefs. Ibn al-Jawzi and al-Dhahabi mentioned it using the weak صيغة التمريض (passive or unconfirmed form) "ruwiya" (it was narrated). Furthermore, signs of fabrication are evident in this story, including: the contradiction in the narration regarding the cause of hunger, al-Tabarani's rejection of Ibn al-Muqri', the falsity of the 'Alawi's claim that he complained to the Prophet, and the unknown identity of this 'Alawi. One should not occupy oneself with such stories unless they possess an authentic chain of narration.