No, it’s not made up. From here. 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance. Some psychologists refute it of course, but it is real . . . speaking from experience.
Seems she has not moved on from denial yet. She may need professional help in getting past it. Unfortunately, grief is different for different people. I would venture to guess something else might be going on as far as a chemical imbalance. She might have developed a touch of OCD because of the trauma. More the obsessive rather than the compulsive.
She needs to have her family intervene on this. If this goes on too long, it could be potentially damaging to her children. Don’t YOU do this, but try to bring it up in conversation with her family: “how’s John’s wife handling this? Is she getting along okay?” etc. Unfortunately it’s not your place and only the family can decide when enough is enough and where their boundaries are.
Good luck.