<Tr> <Td> Richard Riehle </Td> <Td> Walt Finnerty </Td> <Td> 45 </Td> <Td_colspan="2"> Main </Td> <Td_colspan="3"> Recurring </Td> </Tr> <Tr> <Td> Bret Harrison </Td> <Td> Brad O'Keefe </Td> <Td> 65 </Td> <Td_colspan="2"> Recurring </Td> <Td_colspan="3"> Main </Td> </Tr> <P> Sister Helen (Miriam Flynn) is the nun and principal at Lily, Jimmy, and Henry's school . She frequently tries to tell Sean and Claudia how to raise their kids, whom she is always berating at school (Lily's skirts are too short, Jimmy's hair is too long, etc .). Sean once caused her to use the F - word . </P> <P> Dean Peramotti (Mike Vogel) was the drummer of Sean and Eddie's band . He and Lily dated until she cheated on him with Brad . </P>

Who played the nun on grounded for life