What is the appropriate response to someone who says that Negus Asmaha, who was a Muslim, did not rule by Allah's law?

The Negus was excused for not implementing all the Islamic rulings because he was in a land of disbelief (Kufr), most of the rulings had not reached him, and he was unable to declare his Islam or emigrate. The Prophet, peace and blessings be upon him, approved of his state and prayed over him. His situation resembles that of the Believer from the family of Pharaoh. And whoever believes in the Prophet, peace and blessings be upon him, in a land of disbelief and is unable to emigrate, or declare his religion, or learn all the laws, he is a believer from the people of Paradise; because obligations are according to one's capacity and ability. He is not obligated to do what he is incapable of, nor is he condemned for what he did not know the ruling of.