‘And Noah awoke from his wine and knew what his youngest son had done to him.'
After Noah's careless abandon he has to face the unpleasant consequences. This is always the case with sin. It is quite clear that whatever Ham had done was looked on with the utmost seriousness.
“Had done to him”. It was not the discovery of his father's condition which was his sin, but his consequent behaviour. We note that Ham is said to be his youngest son. Thus the order in which sons are given is not necessarily that of seniority. See 10:21 which also suggests that Japheth was the second oldest.