Bringing up the very logical observation that he needs his passport for such a trip and how did he manage without it is not an unreasonable question.
Maybe at this point it doesn't matter anyway.
Giving yourself a solid game plan as you prepare to detach will help make it more real and maybe bring you some feeling of control over the situation.
You are certainly not in denial and understand that there really is nothing you can do but save yourself and child.
I am very sorry you are facing this. Addiction is so cruel and relentless.