Daughter is being bullied at school and principal does nothing?

the principal is a former jock (suprise, surprise) big deal during high school and washed out after tha, anyway the bully is his nephew who already has the obnoxious, arrogant attittude of a stereotypical jock he says sexually suggestive things to my daughter and he also slaps her butt, lifts up her skirt and he calls her fat and ugl;y, and it's ridiculous! but his uncle just says boys will be boys. my daughter gets teased by everyone else too and I'm sick of it. why doesn't this asshole do anything. i've talked to him, yelled at him and demanded that he do his job but being a jerk he's fine with what is gonig on./ what can i do about this>?