William was also a family man. After the death of his brother, Sir Thomas, William's sister-in-law Maud, widowed at age 25, called upon him to help in financial matters and to manage her estates in North England while she was busy in the south securing a future for her three children. William had been named one of the executors of his brother's will. Along with Cuthbert Tunstall, a distant kinsman of the Parr's, they provided the kind of protection and father figure which was missing in the lives of Maud's children. William's children were educated alongside Maud's children.