Christians, how would you have responded to Ivan's contention that the Problem of Evil is insoluble?

The problem Dostoevsky had if he could not satisfactorily answer the question is not taking into consideration his brother's reality was one dimensional, as all atheist are. His brother's preception of the world was through the heart of man, which is incessantly and progressively evil, there he is correct but "the beginning of wisdom is fear of the Lord,"if he had any wisdom then he would understand why man can not save himself and that is why we have a SAVIOR. But then again maybe that was Dostoevsky's answer because this man had a lot of insight but being an atheist his brother has an automatic truth blocker, which is a defense mechanism for subconsciously the atheist knows that if they could see through their life's delusions there lays the danger and that danger is truth and they can't handle the truth.