If your ex is proposing to leave your son alone in the morning and after school, I would simply summarily decide that it's in the best interest of the child to remain with me until *he* can decide if parenting is his priority or not. The 4 to 9 + EOW (every other week-end) sounds like a good plan. It removed the responsiblity on you to play taxi for your ex, and it keeps your son safe all the while giving him time with his father.