To answer your questions, you wait as long as you want to wait. You are the only one that can determine when to file, but I don't think you are ready to do so if you are asking this question. If he's in crisis, it's going to take many months, even possibly years before his crisis is resolved. If you were to ask him about the relationship and/or reconciliation, you may very well get answers you do not want to hear. It could very well push him into filing...is that what you want?
For now, be a friend, listen to what he says and sift through the conversations and you will discover things that you weren't aware of. If you can be a good listener, don't ask question...just listen, he may open up to you. They do love to talk about themselves. You started out as friends, then be a friend again. You will need to dig deep for patience because this is a marathon, not a sprint and it takes a long time for them to get through this crisis.
Keep the focus on you as much as you can. Keep your expectations at zero for the man you knew is gone and has been replaced by his mirror image. Live your life to the fullest because time has a way of slipping away and it can't be recovered at a later time. If he wakes up, he will have a lot of work to do to earn your trust again.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
