My dad works at a metal manufacturing factory. He has been working for this same company for the last 30+years. He has never had any disciplinary action against him and never had problems with HR, ownership or his coworkers. There is however a supervisor that is not liked by most employees and my dad feels targeted by him and even comes home in complete sadness with how he gets treated by him. He yells at not just my dad but other employees. The other day he threw a glass by my dad because he got upset about something. He gives my dad the toughest jobs because my dad is one of the more senior operators there. When the machine breaks down he is upset at my dad that the work can’t continue. He even comes by my dads machine and increases the speed of it while my dad is working on it to “work faster”. I’ve never seen my dad sad before about work but this is becoming too much. How would he go about filing a HR complaint. He says everyone is scared to say anything to HR about the supervisor because they are scared of retaliation or even termination. Please help. Thanks!!!