A Brother's Love

LAERTES:
O heat, dry up my brains! tears seven times salt,
Burn out the sense and virtue of mine eye!
By heaven, thy madness shall be paid by weight,
Till our scale turn the beam. O rose of May!
Dear maid, kind sister, sweet Ophelia!
O heavens! is't possible, a young maid's wits
Should be as mortal as an old man's life?
Nature is fine in love, and where 'tis fine,
It sends some precious instance of itself
After the thing it loves.

     Ophelia has clearly been through an immense amount of stress lately. First, her father forbids her to see the man she loves basically because he says she's not "worthy". Then Hamlet is cruel to her, claims he never loved her, and kills her father.  On top of that, her brother has left her and her father is not buried with the proper ceremony. Ophelia pretty much cracks under all the stress from all the terrible things that have happened to her lately. Also, from the previous scenes between Ophelia, Laertes, and Polonius, the audience gets a clear idea of how controlling Polonius and Laertes are of Ophelia. They basically talk down to her and treat her as a child who is incapable of making her own decisions. However, despite all this, it is made pretty clear that Laertes really does care about his sister and her well-being.
     Laertes comes back to Denmark upon hearing the news of his father's death. As soon as he sees Ophelia in her current state of madness, he becomes very upset and laments the loss of her wits. He wishes that the heat would "dry up [his] brains" and that the salt of his tears would burn sense out of his eyes. He then vows to get revenge for her by saying "thy madness shall be paid by weight". He plans on killing whoever killed his father to get revenge not only for Polonius, but also for Ophelia, since she has gone mad as a consequence of his death. He continues to refer to her tenderly and talks about how moving her madness is. 
     Laertes also comments on the mortality of Ophelia's wits, saying that they were "as mortal as an old man's life". He is basically calling her fragile and weak as an old man. Then he also says that nature deals with love in strange ways. He claims that when something someone loves dies, nature will send "some precious instance of itself after the thing it loves". This means that he is claiming that nature took Ophelia's sanity and sent it away with Polonius because she loved him. 
     This speech as well as Laertes's reactions to Ophelia prove that he really did care about her and tried to do what he thought was right for her. Laertes does try to control Ophelia and tell her what to do. However, he is nothing but kind to her and laments at her madness. He had good intentions, but he went about executing them wrong.