OMG no its not illegal, not where I am from at least, thats what a salary is one set amount of money you get paid, regardlress of hours! I was an accountant in public, no longer in public now, but are you kidding me I use to work 80 hours weeks, if i got paid over time i would have been a millionaire, tahts funny though, so no its not illegal. If he is asking her to work an extra day and that wasnt in the signed contract/ agreement she can probably talk to him, but again no lol i cant imagine that being illegal, if she was hourly, then yea, but salary no ....
still cracks me up