We follow the Institute of Fundraising guidelines that state:
If a third party contacts the charity e.g. a family member of the donor, the charity must be satisfied that the third party making the request is entitled to act on behalf of the individual. It is the third party’s responsibility to provide evidence of this entitlement. This might be a written authority on behalf of the donor, or might be a more general power of attorney for the third party to administer the donor’s affairs. In some cases a formal power of attorney may not be in place and the charity may instead have to rely on a written authority on behalf of the donor.
If the supporter is suffering ill health or does not have the capacity to notify us of changes to their contact details, donations etc. we may, if appropriate, act on requests by the family member. But we will always confirm our action in writing to the supporter directly in case they did not wish the family member to act on their behalf.