First of all we must observe his level of consciousness, and it is best to describe this in human terms, not necessarily in medical terms. We can see he's awake, he's alert and:
-"Hello sir"
-"Hi"
-"How are you today?"
-"Very good"
He is also attentive to the examiner. One can describe his level of consciousness as awake, lethargic, stuporous or comatose, and awake means just as you see that he's awake attentive; lethargic would mean that he's sleepy but aroused easily, arousal - even to minimal stimulation; stuporous means that he is lethargic or sleepy but requires more vigorous stimulation to arouse; and comatose means he cannot be aroused by any stimulus. Again, though, it's easier just to describe what you see in regular language and not necessarily to use medical language.