I am a law school graduate currently awaiting Bar results. What I offer is mere information, not to be construed as forming an attorney client relationship.
First, it DOES sound like definite sexual harassment. This is a very vague area of employment law issue, but leaving such messages (as opposed to just passing comments like pretty hair or nice dress) is definitely something not to be tolerated.
I suggest you read the employment labor law main heading under freeadvice.com's home page and also all applicable subsections, like sexual harassment.
Then, I suggest contacting an employment labor law attorney at attorneypages.com (within your state). Many of them offer free consultations. Also, try your local community guide section in the yellow pages. Check under legal services in that community guide and you might find some employment labor law organizations that offer aid to clients like your wife at little or no cost.
hope this helps.