Are these statements attributed to Moses and Abraham (peace be upon them) regarding the throes of death authentic?

The authenticity of the story of Ibrahim with the Angel of Death is unknown. However, Imam Ahmad narrated, on the authority of Ibn Abi Mulayka, that when Ibrahim passed away, he was asked: "How did you find death?" He replied: "My soul was wrenched out with affliction." It was then said to him: "Gently upon you."

Al-Qurtubi and Al-Muhasibi mentioned other narrations about the intensity of the death of Ibrahim and Musa, but these narrations are from the reports of the Children of Israel, which are neither to be believed nor disbelieved. It is permissible to recount them for consideration.

Ibn Kathir pointed out that there are many reports from the People of the Book concerning the Angel of Death coming to Ibrahim, and Allah knows best regarding their authenticity. A Marfu' Hadith was narrated concerning this, which Ibn Adi described as false.