I have family members like this and the honest answer is addictions. Make plans to do anything with them, even to their benefit, and they delay or change the times three or more times. When I used to keep giving them the benefit of the doubt, I could see once they showed up they were coming down from something and couldn't keep the story straight re why so much rescheduling. And yep, some of them had little kids. I've had to move away from all that, I couldn't really help, just enable and that wasn't right to do either.