My brother has an iPhone. He passed away but I do not have his passcode. He had written down an Apple ID password of Phone77?

My brother had an Apple iPhone. He passed away on Tuesday. I do not have his passcode. I did find a document for his hearing aid where he had written an 8 character text under which was the text Apple ID password. I will be the executor of his estate. What can I do to reset his passcode?