We don't know why the father was sleeping. Perhaps because he's a lazy bum yes, but perhaps he wasn't feeling well or was just napping after lunch like many people do. After all there was someone of babysitting age in the house and that kid (the 13-year-old) probably thought that as long as his brothers weren't hollering or crying or making excessive noise then it meant they were behaving. A mobile home is a small place, you'd expect to be able to notice if small kids are getting into trouble and in fact the teen became concerned when he heard the dishwasher because it wasn't a noise he was expecting to hear at that time of the day. Of course it took him some time to realize that the dishwasher wasn't supposed to be on but familiar noises, even when heard outside of their usual time frame, don't always immediately register as emergencies.