Why didn’t Imam Ali (PBUH) defend Fatimah (PBUH) when they attacked her house?

Answer

In the name of Allah, it is established in our reliable sources that the Prophet (PBUH&HF) had informed Ali (peace be upon him) of what would befall him and his daughter and commanded him to be patient. In some sources, it is mentioned that when Ali (peace be upon him) heard this, he stood up and sat down again due to the severity of what he had heard and asked the Prophet (peace be upon him): "Should I remain patient while the sanctity is violated?" The Prophet replied: "Yes, this is Jibra’il (Gabriel) informing me." The Prophet then said: "Tell Fatimah not to call out to me at the time of the enemy's aggression," and perhaps this is the reason why Lady Fatimah (peace be upon her) called out to Fiddah instead. Allah is the All-Knowing.