"although I know he is still to deep in the fog for it to make a difference, but just maybe it will?"
Don't expect it. Also, take it from me.... if he comes back too quickly without really learning a lesson about what it's like to lose you and his children... the chances are higher it could happen again. That's my own personal experience speaking there... This will take time. He needs to feel the loss and what it's like to lose all of you, and you will need to detach much more and do a lot more growing.
I don't think you should have offered to get his car for him.... but since you are. Make sure you are attractive, friendly, happy, joking, flirty and COMPLETELY INDEPENDENT. Be an interested listener, but insist that life is great. Imagine every guy wants you and this lughead husband can only wish it were him... Life is good!!!
There is no arriving, ever. It is all a continual becoming.