Do what you are doing. Be there for him. Talk with him. Let him talk to you. A little playful banter shouldn't be a problem, but I would not take it any further anytime soon, and especially not until a divorce is final. Give him ((hugs)), lots of them and promise that the next time you see him you will give him a real hug...but that's it. He needs to get through this before getting involved with anyone else, especially someone who is already attached to him.
Life is about the journey and not the destination,
so what better way to know life
than to wander all the roads and paths set before you.