Occupied Royal Palaces, such as Buckingham Palace, are not the private property of The Queen. They are occupied by the Sovereign and held in trust by Crown Estates for future generations.
The Queen privately owns two properties, Balmoral Castle and Sandringham House, which are not publicly funded
Mamya is right. Anyway, who would condemn a 90 year old lady to live in what could be a death trap? For shame! She's on the parish and is entitled to relief.