If push comes to shove you could always put her on a 72 hour psychiatirc hold, but that might put a strain on th relationship. Dealing with death can cause us to toss our rationality out the window. The best advice I can give is to have her talk out her feelings with you and for you to try to ease her through the grieving process. It may take time, and something else that might help is keeping her occupied with activities that she enjoys that way she isn't just sitting and thinking.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell
