In the first act of the play, we meet Capulet as one of the patriarchs of the two...
feuding clans in Verona. While it is true that he does not wield a sword or throw a punch himself, it is obvious that he could stop the violence his loyalists are causing if he really wanted to do so. He does not.
The next time we see him, he is talking to Paris about Juliet: Paris wants to marry her. Capulet sounds like a loving and reasonable father when he tells Paris that Juliet is too young and that
My will to her consent is but a part.
Capulet makes it clear that he will never consent to anyone marrying his daughter without her approval.
We also know Capulet is capable of being good-hearted and is willing to be hospitable even to his enemies when Romeo and the others show up to his party. He knows Romeo is there (Tybalt tells him) and yet he does not take any action against him.
So far we have mixed messages indeed from Lord Capulet. He hates his enemies but lets them stay at his party. He insists that Juliet must be able to choose her husband---and then he goes and does something completely contrary to that in Act III.
Juliet's cousin Tybalt has been slain by Romeo, and Juliet is inconsolable. Of course her parents assume she is crying for Tybalt, when in fact she is mourning the loss of her husband, Romeo.
There is little explanation for what happens next other than Capulet wants to help his daughter get over her grief and grabs onto the first idea he comes across in order to make that happen. He arranges for Juliet to marry Paris immediately.
Lady Capulet delivers the news, but Juliet is not thrilled as her father expected her to be. In fact, she flatly refuses to marry Paris--or anyone else, for that matter. Capulet's reaction is extraordinary. He yells at her, he curses her, he calls her names, and he vows to disown her. And his language is such that we believe him, and so does Juliet.
Hang thee, young baggage! disobedient wretch!I tell thee what—get thee to church a ThursdayOr never after look me in the face.Speak not, reply not, do not answer me!My fingers itch.
Clearly he wants to hit Juliet for her insolence, something she refuses to explain to him.
Juliet continues her stubborn refusals, and Capulet continues his tirade against her, saying that he has never done nothing except try to make her life better. Now that he has made such a fine match for her, he expected Juliet to be grateful and therefore obedient. When she is not, he continues his tirade:
Graze where you will, you shall not house with me.Look to't, think on't; I do not use to jest.Thursday is near; lay hand on heart, advise:An you be mine, I'll give you to my friend;(200)An you be not, hang, beg, starve, die in the streets,For, by my soul, I'll ne'er acknowledge thee,Nor what is mine shall never do thee good.Trust to't. Bethink you. I'll not be forsworn.
This is a serious and significant threat, and Juliet obviously believes it because she takes drastic action to avoid having to marry Paris.
When Juliet refuses to obey his wish, Capulet is obviously angry, angry enough to give a detailed threat about disowning her. We can also assume he feels softer emotions, such as hurt and disappointment, since this all started because he wanted to comfort her. In any case, his reaction is explosive.