Rose asked:
my friend was laid off last year, he is getting severance from his exemployer plus medical benefits. Now he has a job, offering benefits, his employer found out. They have asked him to pay back his the employer portion of the medical insurance premium. Is it legal?

nope get a lawyer !!!!!!!!!!!!!!!!!!!!!
Yes, of course it is. It sounds like your friend was trying to get over and what he did may constitute insurance fraud. He should pay back the employer and hope that they don’t choose to make a bigger issue out of this.