As children change people.

I have one friend, this story happened to him, I write what he told me.
He has been married for like three years, and all have been good exactly to the moment until the family have not had a child. With a new baby, his mother, and part-time wife of my friend was crazy, like it replaced.
There were scandals, quarrels, swearing, but the latest incident has put an end to their family. And it was like this:
Saturday morning the husband sent ten o'clock in the morning the wife to the store for diapers for the baby after giving her money for them. She left at ten o'clock in the morning, and returned only four hours a day, drunk in the trash, no diapers and no money. She came and straight into the shoes of went to sleep on the bed.
To the question - what how to understand it? The wife of my friend just started yelling at him saying I did not a person? Do I not have the right to drink what?
Then got out of bed and hit my husband with his fist in the chest, and this despite the fact that at the moment he was holding the baby. After that, she went to the kitchen and there began to beat the dishes, smashed the TV and broke the chandelier, even threw a stool against the wall. My friend took a lot of effort to calm her down.
Then he decided to leave her money, and took the child in time to move in with his parents. He thought it would help that she's raging and calm down. But he only thought so. Flat way it was his.
He lived at my parents for three months, my wife did not communicate at all. Three months later from a third party, he learns that his wife opened a criminal case for possession and distribution of narcotics, and robbery with a group of people on a stall, where they brutally beat up the seller and customer. For everything about everything she's facing 11 years in prison.