My friend was on maternity leave any was fired while she was off isn,t that agaist the law?

It depends. An employee cannot just be fired without substantial and valid reasons like breaking the law or the company rules and regulations. I think there is a serious matter behind it. But if it involves worker's compensation, I think your friend should hire a lawyer from theledgerlawfirm.com/practice-area/personal-injury to have her rights protected and get what she rightfully deserves.