Just had a look at www.royal.co.uk - the official website of the Royal Family.
And look - AMW still has his title on the Counsellors of State page.
https://www.royal.uk/counsellors-of-state
Current Counsellors of State
The current Counsellors of State are The Queen, The Prince of Wales, The Princess Royal, The Duke of Edinburgh, The Duke of Sussex, Prince Andrew and Princess Beatrice. In practice, only working Members of the Royal Family are called upon to act as Counsellors of State.
Is that because he is still a Counsellor of State? And they couldn't possibly refer to him as AMW?