ISLAMABAD: PPP Chairman Bilawal Bhutto Zardari has advised his father and former president Asif Ali Zardari never to comprise on democracy and democratic norms.In his statement on social media website Twitter in connection with the Father s Day on Sunday, Bilawal Bhutto said during 11-year imprisonment Asif Zardari tolerated worst torture but never gave in and continued struggle for restoration of democracy in the country.He said his mother Benazir Bhutto was assassinated by extremists but his father led the party and gifted a democratic Pakistan to the masses. The PPP chairman paid tributes to his father for strengthening democracy in the country.