Everything he said was correct if someone says rule by the book of Allah that doesn’t make them AS and if you reject the book of Allah (sharia) then you left the fold of Islam
وَلۡیَحۡكُمۡ أَهۡلُ ٱلۡإِنجِیلِ بِمَاۤ أَنزَلَ ٱللَّهُ فِیهِۚ وَمَن لَّمۡ یَحۡكُم بِمَاۤ أَنزَلَ ٱللَّهُ فَأُو۟لَـٰۤىِٕكَ هُمُ ٱلۡفَـٰسِقُونَ﴿ ٤٧ ﴾
So let the followers of the Gospel judge according to what God has sent down in it. Those who do not judge according to what God has revealed are lawbreakers.
Al-Māʾidah, Ayah 47