Sounds to me as though you've shared an understanding which far exceeds most. How lucky you are to have (had) that with her.

Have faith in what you mutually share. Confide in her about your fear regarding the accident (whatever it entails), so you can allow yourself to get beyond that obstacle which presently seems to be blocking you.

Once past that, then tread lightly. The reason I say that is, from what you've posted, you have put all your eggs in one basket regarding your feelings for her. It sounds as though all your hopes for happiness ride on this one person, and that can be a recipe for possible emotional disaster, not because of what YOU feel, (as this you're fully aware of), but because you cannot possibly know exactly where she is at present regarding her feelings for you in return.

"Have not high expectations, but rather abundant expectancy". In other words, hope for the best, but expect the worst.
Approach this with with the understanding that it may/may not end up as YOU hope for it to, yet the possibility of success as you seek is still probable.

It's a great responsibility to place one's entire hopes and dreams for emotional success solely upon another. Despite the circumstances, (the level of the relationship, the intensity of bondings, etc.), to invest oneself into another in that way can almost always ensure disappointment at some point....and it's usually always a disappointment we create for our own selves.

Talk to her without expectations of success. You both share quite a past, and seem to have something many do not...mutual understanding.
Sounds as though she also has a full plate at this time, and it's vital that you allow her to express to you where she is at present. Be her friend first. Go from there.

Maybe, first try to rekindle the friendship that you both share. Reignite that bond first. Utilize that as your path toward something deeper and more meaningful. It is important that you understand where she is emotionally, as well. And if you approach this opportunity without expectations she will undoubtedly also sense the same, therefore chances of it going further increase.
Take it slowly. Express and discuss your fears. It's so important that the both of you understand each other. After which, and if mutually bound.....Yay for communications!

I wish you all the best. Good luck.

Shangrala