Your decision about what to do would be largely based on the outcome you expect. If you believe that this visit would only be a fling even if it involves sexual intimacy then that is all it is. If on the other hand you believe that he is going to seek a relationship even a long distance one it is another. Of course, with the distance being an issue, you've got to ask yourself what sort of a relationship that would be.
He may believe that sexual intimacy is possible because he knows how you feel about him. Yet, some things are best left in the past. Whatever you have had or could have had at one point in your life does not mean it would be the same now.
It may be best to do what is safer and not get hurt.
There is nothing wrong in seeing him and having some time to catch up on things. Your feelings serve you a purpose (whatever that is only you know)
You may be found of him and holding onto the feelings from the past (in a way wanting to re experience them) Change is good and there is always going to be change in one's life. As long as you know what you want, then pursue it (that involves risk taking).