Will owner reduce the rent?

A friend of mine went to court last week as witness and the defendant turned out to be a guy who did all kinds of serial crimes and he was masturbating outside the bed room window of my friend's apartment around 11pm at a dark night and the neighbor saw him and called the police, who arrested him. However, the couple were watching TV with T shirt and short on and didn’t know anything till the policemen arrested the guy. The guy entered there through a broken brick wall.
Can my friend sue the owner for the broken wall or how can my friend ask the owner to reduce the rent?