person A: i have a slacker coworker that drives me crazy he gets to work late everyday and does the minimum to get by
person B: Is the boss aware or does he seem to skate by unnoticed? 
person A: she is aware but doesn't feel the need to do anything about it. that's what makes it worse
person B: Is there an HR department you can take it to?
person A: not directly inhouse
person B: Sounds like it might be time to sit down with the boss and discuss your thoughts and feelings. If moral gets too low it's not good for anybody.
person A: i've tried. she says she will talk to him but nothing changes.