I heard that when Lady Fatema(pbuh) was attacked by Umar in house and the scence of burning door happened, Imam Ali(pbuh) was inside the house but did not come to help. Is it true? Can you please shed some light on this topic? I have to give information to my friend. thanks alot.

These days Alhumdulillah Majalis are being recited where in detail they are reciting.
Imam Ali as had pledge with Rasul saw that do not fight madina is haram like Makka therefore for the respect of the city and pledge when Imam got power he moved to Kufa because he knew that other people will impose battle on him and also Bibi Fatima as stoped him