Accessing a deceased relatives’s phone with death certificate

I am very sorry for your loss

See this link for instructions on how to access your late brothers Apple ID

How to request access to a deceased family member’s Apple Account - Apple Support

Thanks for letting us know you are in Scotland. The links provided assume U.S. laws are in effect. Probate law in Scotland may be quite different than in the U.S. Of course you will be required to comply with probate laws in Scotland. Again you may need the services of a Solicitor to work this out especially if your brother was an adult and had no will. Apple will comply with the laws in Scotland that apply.

Review this section. Two links provided:

Request access with a court order or other legal documentation

In the U.S. and other locales, you can request access to a deceased person’s Apple Account and data with a court order that names you as the rightful inheritor of your loved one’s personal information. In some jurisdictions, such as France, Germany, Japan, Australia, and New Zealand, alternative documentation and process instead of a court order are accepted. Where applicable, the court order needs to specify:

• The name and Apple Account of the deceased person.
• The name of the next of kin who is requesting access to the decedent’s account.
• That the decedent was the user of all accounts associated with the Apple Account.
• That the requestor is the decedent’s legal personal representative, agent, or heir, whose authorization constitutes “lawful consent.”
• That Apple is ordered by the court to assist in the provision of access to the decedent’s information from the deceased person's accounts. The court order should be addressed to the relevant Apple entity.

If you have a court order with this information, or if you need additional help, please contact Apple Support.

First of all, sincere condolences on the passing of your brother. I lost my brother way too soon too.

Read the support document closely. Did your brother have a will? If so then who is the executor? If not then you may need a probate judge’s order. Was your brother a minor? No one here can give you step-by-step instructions because we don't know the circumstances of your situation.

Unfortunately you may wind up needing the services of an attorney.