Is it true that the book "Al-Funun" by Abu al-Wafa' Ibn 'Aqil al-Hanbali is lost, and did he have other books, and who is Ibn 'Aqil and what was his belief and knowledge?

Abu al-Wafa Ali ibn Aqil al-Baghdadi al-Hanbali was born in the year 431 AH. He pursued religious studies, taught, debated, and issued fatwas. He was intensely eager in his pursuit of knowledge, continuing until he reached the age of eighty. He authored numerous books, among them "Al-Funun," which is said to have reached eight hundred volumes, and also "Al-Fusul" and "Kifayat al-Mufti." He was influenced by the Mu'tazila in his early life, but then repented from their views and wrote works refuting them. He passed away in the year 513 AH, and a large congregation prayed over him.