Matthew Leone has a broken jaw and one third of his skull has been removed because his brain is swollen after he was beaten earlier this week.
"Matthew is a hero in my book. He's an angel. He put himself at great harm," said Nathan Leone, victim's brother.
Nathan Leone says his twin brother Mathew was walking to a bar in the 1300- block of West Ohio Tuesday morning.
"He walked about half way there and witnessed a guy beating on his wife. Where we come from, violence against women is absolutely disgusting," said Nathan.
Nathan says Matthew, who is the bass player for the Chicago-based band Madina Lake, tried to stop the fight, asking the man to relax.
"That kind of worked initially, he got in the middle and tried to make sure she was okay. The guy proceeded to beat him from behind," said Nathan.
Matthew was beaten unconscious and taken to UIC Hospital, where he brother says he's improving.
"He is talking and in and out of consciousness, more or less. He does recognize me," said Nathan.
The band's fans have reached out to the twin brothers, sending well wishes. Nathan Leone says that support has been amazing, even overwhelming.
"Of course there are a few evil people in the world, but there are so many more amazing people," said Nathan.
Chicago police arrested the husband and charged him with misdemeanor domestic battery. Authorities have not released the suspect's name and he has not been charged in connection with Leone's beating.