It's not "illegal" in the sense that people, including businesses, can look to settle claims with one person making various payments for another. But while it's not illegal to ask, you are under no obligation to make any payments to or on behalf of your coworker unless you were at fault in injuring him. d on what you write, you were not at fault: if he was on top of you after attacking you, and his leg was broken either during his initial attack or when you defended yourself by pushing/throwing him off, that would not make you liable for his injury (self defense is a legal defense to a claim you injured another, so long as the facts support the assertion of self defense). So your employer can ask, but you are not, based on what you write, required to pay. And note: employers may not take money from employee paychecks without employee consent: to do so is illegal, and you could file a wage complaint with the department of labor.