I'm not sure we know what happened that night.
The main evidence made public so far appears to have been reported by her husband, who has lawyered up and is apparently not helping with the investigation.
The car's position, the pill bottle location, the dogs being loose & possibility of her body being found in a location with fencing she would have to cross on a cold dark icy night are all suspicious.
Due to her recent stoke, ND was vulnerable in many ways IMO. Many people on social media have described her as a sweet lady.
How sad her life ended as it did.
MOO