A wrongful death lawsuit can only be filed by a "personal representative" of the deceased. The representative could be a surviving spouse or the next of kin such as children, parents, and other blood relatives. A Chicago wrongful death attorney will guide you through filing a case as an estate or individual plaintiff.
In some circumstances, the heirs and beneficiaries can also file a wrongful death lawsuit. However, circumstances change if the deceased was also responsible for their death- this is called the comparative factor.