Having to deal with the loss of a loved one is not something that anyone wants to deal with. When a member of your family has passed due to negligence that can be proven in a court of law it is wise to pursue for compensation to pay bills, the funeral, and everything else that comes with the loss of a loved on.
The standard of proof in the United States is typically preponderance of the evidence as opposed to clear and convincing or beyond a reasonable doubt. Keeping in mind that no matter what you are going to do, if you think you should pursue you should find the best lawyer.