It bothers Connell that Mairanne accepts the violent behavior of other people becuase it is waht makes her dependent on others. So, he did not want guys to be violent towards Marianne, who is subjected to these people.

In the novel, Marianne suffers from domestic violence by her father and her brother. In particular, her brother Alan is very violenst against her for different reasons:

• because  he has not got the control over everything and since he feels he can not have total control towards her sister, he behaves aggressively;
• because he took the father's position who also was aggressive towards Marianne;
• because he is afraid and therefore he is violent;
• because violence is a cultural aspect.

It comes into surface the typical vitorian idea of the householder where the father have to manage everything about the family and every decision is his. Therefore, this brings the man to be violent. Consequently, Alan is a typical victorian character. Although the novel is a Postmodernist one, Alan is not a Postmodernist character, since in Postmodernism there is a specific idea of a male gender character.

Alan uses a very vulgar, violent, low and aggressive language.

When Alan becomes totally aggressive towards Marianne in the section July 2014, when he tries to make himself understood of why he has been so violent, he justifies himself saying he does not want her sister to go out with Connell, becuase he does not belong to the same social class. Indeed Alan defines him a knacker (= macellaio).

At page 239: 

• "Now she knows that in the intervening years Connell has been growing slowly more adjusted to the world...": Marianne does not consider positive that Connell grew up by a process of adjustment to the world because it means he always looks for the cosent of other people and that he is afraid of expressing his own idea. Anyway, Connell seems to be more at ease in Carricklea than in Dublin, since in the small village he was the most popular and since building relationships is difficult for him.
• "Alan come up from the kitchen with a bottle of beer in his hand": it gives the idea that Alan was an alcoholic man. Since alcohol allows people to do what they normally do not do, Alan isprobably a man who is not used to dace problems. However, Marianne is powerless in front of her brother: she feels as if she were in a prison, without any exit way.
• "I thought you liked him, says Marianne. You did when he were in shcool.": reference to when they attended High School when Alan probably liked Connell, since he was famous.
• "I suppose you'd have to ask him": Marianne tries not to answer him because she does not want to give herself away and revealing everything.