When Claudius enters to see Ophelia—who has lost her mind—in Act Four, scene five, of Shakespeare's Hamlet, he seems very concerned for her.
He greets her first:
How do you, pretty lady? (46)
Ophelia responds that she is well and calls God's blessing down on him, but then continues speaking nonsense.
Claudius tells Gertrude that he expects Ophelia's actions are caused by the death of Polonius. Surprisingly, when she recites part of a song, Claudius finishes the last two lines of the song. This might be perceived as a softer, more sympathetic side of the King that we have not seen before—however, in Ophelia's madness, some of the songs she sings are bawdy, filled with inappropriate content that she would never sing if she were in her right mind. While it might appear that he genuinely cares for Ophelia, Claudius sings the remainder of a song that would have been considered vulgar at that time: for a young maiden, and for a King in the company of women.
Ophelia's song laments that the singer's lover promised to marry her before she slept with him. Claudius finishes by singing the remainder of the verses, which is the lover's response to the singer: he would have married her if she hadn't slept with him.
By Gis and by Saint Charity,
Alack, and fie for shame! (65)
Young men will do't if they come to't
By Cock, they are to blame.
Quoth she, 'Before you tumbled me,
You promis'd me to wed.'
'So would I 'a' done, by yonder sun, (70)
An thou hadst not come to my bed.'
When Claudius asks how long she has been in such a condition, we can assume that her deterioration is a surprise to him. He then asks Horatio to follow Ophelia when she leaves and keep an eye on her.
Claudius then speaks with Gertrude, sharing his belief again that Ophelia suffers because of the loss of her father.
O, this is the poison of deep grief; it springs
All from her father's death. (78-79)
This is a particularly ironic moment in that Claudius himself is also guilty of this particular sin, having deprived another child of a father: Hamlet. And while Claudius shows seeming concern for Ophelia, this is still a man who will do anything possible to keep the throne he received when he murdered his brother.