Yes, a vacation sounds like a great idea.
I hear what you are saying and I don't know that it's a bad thing but I think you should think long and hard about your motives.
He does have his family to help him research rehab, plus he is a grown man, he should be able to get help if he needs it. He would probably start in a detox facility anyway and they can assist him in getting help as well.
What if 6 months from now you are seeing someone that is amazing and wonderful and you are incredibly happy with them? Do you want to take time away from that and all the other good things in your life to hold your ex ABFs hand?
It's not selfish and it's not mean to want to start fresh with your new life, to pursue what you want to. This is all so new, so you can't clearly make decisions like this if you know what I mean? You haven't even been out of the tornado of drama long enough to let your emotions settle a bit. Time will tell you whether or not you want to get involved back in his drama. He may never seek recovery so it may never come up, I hope he does, but he might not, or maybe not for years.
In the meantime, I really hope you will go and have a terrific vacation and plan a lot of fun things just for you.