Note : Hospitalized incest daughter 's condition is grave but stable , police say . Fritzl imprisoned and raped daughter , also killed her child , police say . Wife of Hans Fritzl was too scared to question him , her sister says . Fritzl 's wife insisted on keeping family healthy , according to her sister .
NEW : Hospitalized incest daughter 's condition is grave but stable , police say . Fritzl imprisoned and raped daughter , also fathered her children , police say . Wife of Josef Fritzl was too scared to question him , her sister says . Fritzl 's wife focused on keeping family healthy , according to her sister .