What steps do I need to take in order to go forth with a wrongful death law suit?

So if your brother was a resident of the home, he may be an insured under the policy, such that if his negligence caused or contributed to your dad's death, then the insurance company Would most likely be a source of recovery. If your brother was not a resident and thus possibly not insured under the homeowners policy, then it would be more complicated. Now if your brother was not insured under the policy, perhaps because he did not live there, but your brother owned a house of his own, then that insurance policy may be a source of recovery depending on the policy language. However all of this is speculation until more facts are known, such that a full analysis can be explored. You need to retain counsel to investigate all of the facts of the case to make a determination. What state did this happen in?