Mr Prewett was a pure-blood wizard. He was the brother of Ignatius Prewett. the husband of Mrs Prewett, and the father of Molly Weasley née Prewett, and Fabian and Gideon Prewett. He was the maternal grandfather of the Weasley children. He was also the father-in-law of Arthur Weasley. He could also possibly be the nephew of Muriel. He may have owned a chess set and may also have had a big nose.