Our brother passed suddenly in SC yesterday without a will and without disclosing the truth about his accounts?

We are grieving and having to deal with the business side of things at the same time. We loved him dearly but being diagnosed OCD/paranoid Schizophrenic, he did not have a great handle on reality. He received benefits for almost 30 years and has left us totally at a loss as to how to beging to resolve his business life. Can you tell me if there is an official, proper way to provide his Social Security Number to a government office that will help reveal where he might have done his banking, paid his bills, literally EVERYTHING has been left as if he was going to live forever. We want to spend our time loving him and doing what is good for our aged mother who was his caregiver. There must be some resource in this age of technology. Under no circumstances are people who want to hurl insults about greed or ugly minded things to answer. I will report you for abuse. I am hurting and want to help my family. Thank you.