When Fatimah said that, meaning when the Messenger of Allah ﷺ was suffering the agony of death that he suffered, Fatimah cried out, "What anguish!"The Messenger of Allah ﷺ said, "My dear daughter, your father is now facing what Allah will not spare anyone from until the Day of Resurrection."
لما قالت فاطمة ذلك، يعني لما وجد رسول الله ﷺ من كرب الموت ما وجد قالت فاطمة: وا كرباه. قال رسول الله ﷺ: يا بنية إنه قد حضر من أبيك ما ليس الله بتارك منه أحدا لموافاة يوم القيامة.
Ahmad (12434) narrated it from Abu Nadr, who said, our teacher Mubarak told us, from Thabit Bunani, from Anas, and he related it. Its chain is hasan because of Mubarak, who is Ibn Fadala (with a fatha on the fa) al-Basri. He is disputed, but his hadith is hasan when he states his source explicitly, because he practices tadlis and evens out chains, and he did state it explicitly in the second chain.Moreover, he was not alone in narrating it. Abdullah bin Zubayr al-Bahili, Abu Zubayr, also related it, saying, Thabit told us, from Anas bin Malik, and he related something similar, adding in it, "There will be no distress upon your father after today."Ibn Majah (1629) and Tirmidhi in his Shamail (380) both narrated it from this route.