What happens after they overdose

My brother has been missing in another state and is deep into his addiction. No one has heard from him in a few weeks. If he does die, how will they inform the next of kin? If anyone can tell me what the process is so I’m prepared, that would be really helpful. I’m not hopeful for his future as we thought last years overdose and hospital stay was his rock bottom. He’s my only sibling and it’s breaking me.