At the end of the conversation, her mother told him that she’ll be going to pick his younger sister from the school and purchase some groceries. No one else was available to come to look after him in the meanwhile. She couldn’t take him as he was already feeling low. Also, Baby Girl, a pit bull gets scared if left alone. Yes, pit bulls aren’t like that but Baby Girl has never been alone and so Shane was going to look after her too. Nobody had any idea of what was about to happen within a few hours when Shane was left at home.