How can this Happen

How was this young man able to be around this baby knowing he already injured him once.  Instead of jail he needs to be placed in a mental health hospital to get the help he really needs.  I was reading this story and it almost brought tears to my eyes but I was so angry because of the circumstances. This child has been brought up in a very bad situation of all types of abuse then to witness a suicide he is unstable and i don't think mental health can help him but we have to try.  Then the only person who should be charged with murder is the mother she knew what he was capable of and she still left the children unattended and this happened.  Maybe the leg breaking was an accident but it was enough to have cause to watch him more carefully when he was with his sibling.  Where was she and what made him kill his brother is the question I'm asking.Then they want to charge him as an adult and give him life he is a baby himself he can't help the way he was brought up.