Hi my dear wooba, I'm so excited to hear about your super sparkly new life. It's great when the stars align and that whole new life emerges as a whole new you emerges with it. As far as dealing with XH. I'm relaying to you what I know from having to parent with an alcoholic for the last 18 years. Take what you think is best.
IMHO the oldest needs a phone on him when ever he isn't with you. If he is in the same school with the littles just him having a phone is fine, but if they are in separate schools you may need to consider an emergency phone for the next oldest. If it hasn't happened yet there is likely to be a time when XH tries to pick the kids up under the influence or completely forgets them. D18's school when she was small would start calling down the list after only one call to me and more often then not I couldn't answer my phone but I could respond to a text. Next the "sleeping" through phone calls is only the tip of the ice berg. There will soon be days where XH will sleep through feeding them or getting them to scheduled activities.
I often had to order my daughter delivery if I made the mistake of going out of town on her dad's weekends. Other times I'd just come and get her. Once she spiked a fever while she was there and I had to go pick her up and take her to the ER. His GF at the time didn't know what was going on because my ex was ignoring my daughter to try to stay at the party they were at. As soon as I texted the GF she swiftly met me at the ER with my ex. I miss that GF.
All that being said. Your 12yo is now the 3rd parent. It [censored] for him. And thankfully in your house he won't ever have to be, but he more often than not will be at XH's house. 12 isn't too young to talk to him about his dad's drinking. And if I'm really honest with you he already knows. He probably just had no real good way to start that conversation with you, or has just accepted that as his reality. I was clear with my daughter from a very young age about what her dad was/is and what that means for her. You don't need to sit down and say "Hey guys, daddy's a drunk so I need you to report back to me everything he says and does." Or "Hey guys, daddy's drinking is out of control so you need to call me when he passes out and leaves you unattended." But your 12 yo I think you can have a real heart to heart with about taking some responsibility to make sure that you are informed when and where they are at after a reasonable amount of wake up attempts. Making sure they aren't going too long without reminding dad to feeding them or calling you when he said he would, and making that call himself if dad isn't.
