He is able to fully 'comprehend' [=understand completely] what is happening and react appropriately.
I find his attitude impossible/difficult to 'comprehend'.
They are unable to 'comprehend' what had happened.
(..) Who's lending, who's borrowing? - You got any collateral? - Collateral? - Automobile, jewelry? - What is this, Chase Manhattan? You don't seem to comprehend the situation. You have to pay three percent a week every week. I know what I have to do. - Where are you gonna get it? (..)1974 The Gambler