In act 4, what does Laertes's anger show? Reference both his father and his sister.

In act 4 of Shakespeare’s Hamlet, Laertes unexpectedly sails back from France after hearing the news of his father, Polonius’s, sudden murder by Hamlet. He approaches the castle with a mob of supporters ready to avenge his father. He angrily demands to know the circumstances of his father’s death from Claudius, who manipulates Laertes’s grief into a plot to assassinate his stepson/nephew.
Laertes’s fury over the situation indicates multiple things about his character. The first, of course, would be his love and dedication to his family. Laertes comes from a foreign land ready for combat with little notice. His willingness to drop everything and return to Denmark shows just how much he truly cares for his father. The fact that he quickly and enthusiastically agrees to Claudius’s suggestion to kill Hamlet via deception shows that he is susceptible to manipulation because of his blind love for his slain father.
Furthermore, when he learns that Ophelia has committed suicide because of her grief, Laertes is overcome with emotion. Although he says, “too much of water hast thou” about his sister’s drowning, Laertes can’t stop himself from crying. Thus, his rage has transformed to anguish, which is the emotion underlying his original wrath.
In addition to this, his extreme anger shows Laertes’s trait of impulsiveness. Laertes lets his emotions control him, not the other way around. That means he is prone to making rash decisions, which is what ultimately dooms him in the duel with Hamlet.