The thing I think is real interesting is that your wife has been working this way for 6 years without making a protest. Now you're going to turn him over to the Army, Navy and the Marines and demand he be punished for knowingly misclassifying her? My question is still the same. She knew she wasn't a contractor, or should have known, and yet she's been cooperating up to now. Why has she continued to work this way?
I agree that it is one sorry way to treat your employees, usually done on purpose and for meanness (in the sense of cheapness) and we saw so much of it. If your wife was laid off, let go, fired, by this doctor, she would hopefully file for unemployment insurance even though they'd first tell her she wasn't eligible as a contract employee, she'd have to appeal, and the unemployment system would do a fact finding.
And if she was indeed misclassified, they'd approve her monetarily for benefits anyhow and come down on the doctor. But there's only liability in the form of back taxes and penalties, not prosecution for criminal negligence. If they criminally prosecuted everyone who did this particular trick, it'd be like prosecuting every unemployment fraud, there'd be no time to prosecute more serious criminals.