Katchie...I am so glad that your son opened up to you. I would be very careful about telling dear old dad that son told you that. It will build up resentments and cause even more trouble.
The thing is, if he is relapsing you will find it yourself in due time. As you said, you need a few months to get your ducks in a row. I am sort of doing the same thing right now as I financially just cannot separate this second. I do know it will happen and am preparing things for just that. What point is there in even addressing it right this second?
It is great that son opened up to you and that you are such a good Mom. Communication is key. If I remember correctly, he does not drive your children, is that correct? If not then of course that will have to change.
I am sorry you are going through this. We will walk it with you, you are not alone. Keep on working on you and doing the great job you are doing. Remember those three C's and keep marching forward!
Hugs!