My 7 year old forged my husbands signature.

Anastasia
My 7 year old tried to forge my husbands signature on a paper from the principle. He got in trouble for playing army with another student during music class. He got in trouble mostly for being disruptive. My husband is livid about the signature and is acting like our son is headed for a life of identity theft. 
What the hell do I do!! Most kids forge a signature once in their lives but that's usually when they get a little older and at least spell the parents name correctly. 
Any insight would be great!!