Doesn't make sense - if boss insists with this demand then your husband should consult a local attorney
This is not intended to be legal advise or as legal representation. I am a California personal injury attorney . Be aware that every state has its own statute of limitations; and statutes & case laws that govern the handling of these matters.
If he was injured, you should contact my office or an attorney of your choosing immediately regardless of who's fault it was. If his employment is in jeopardy, same answer.
DO NOT describe the facts of your case in an online forum. I know there are a few prosecutors who are members of this site. My statements are my opinion solely based on the information provided, and that opinion can be wrong if your facts are different than what I believed them to be. If you have any further questions or need any further assistance, you can contact me at 314-669-5752 or through my website www.tsalawoffice.com