The Department of Health (England) needs the consent of families to release information of deceased relatives.
135. There are circumstances in which you must disclose relevant information about a patient who has died. For example: [...] 138. Archived records relating to deceased patients remain subject to a duty of confidentiality, although the potential for disclosing information about, or causing distress to, surviving relatives or damaging the public's trust will diminish over time. [...] Usually, if an individual who is known to the deceased is requesting information in relation to the circumstances surrounding the death, it will be appropriate to rely on the above GMC guidance.