His employer was an idiot and later realized it when they were in violation for at least one law. I will give you a hint...you mentioned it already and it is not FMLA.

Im the states I worked (and had employees) you can not fire someone for being injured on the job unless the injury was intentionally inflicted. At that point the Workman's Comp claim can be denied, too.

Have the attorney talk with them and work this out. All parties know you partner was wronged!