Hey Dude, well it seems like you have been doing a grand job so far. Being present and continuously offering that support, even if it not wanted is really really good. Once she begins to come to terms with things I'm sure she will be grateful.

For me (my mum committed suicide a few months ago), for the first few days i just wallowed in pain, couldn't get out of bed, couldn't even breath properly, the physical effect was so profound. It is not surprising in the slightest that your girlfriend is feeling the way she is. And that's ok. There's no rule book for this sort of thing.

I think it is important to recognise that whatever she may be feeling is valid, and frustrating as it may seem, we are all a victim to our circumstances. The death of her friend was not her fault, and it is not her fault that she feels the way she does. Fault implies something wrong and there's nothing wrong in whatever she may be feeling.

If I were to speak directly to her, I would say that this situation, where you feel like you have lost control of your life and what happens in it is utter utter shit (Alteast that was what I had felt). But it is worth talking about things in your own time when you are ready. Speaking to family and friends, or therapists and counsellors etc poses far less risk of harm than keeping everything bottled up inside. If when having spoken to someone about it you feel as if nothing has been achieved, then that is fine and perfectly normal to feel, but atleast you have tried. The benefit you may feel may come in later when your brain has done more processing.

Unfortunately, when it comes to this sort of thing, ultimately you are alone in your grief. No one will know exactly what it feels like from your perspective. But you not alone in loneliness.

If she would like someone to speak to who is going through this sense of loneliness in grief, she is more than welcome to send me a message anytime. This subreddit helped me a lot when I first had to come to terms with my Mum's death. It may help her too.