Can an employer force me to provide the name of my private insurance information to their group ins

My employer is forcing me to provide my private insurance information to their group health insurance is this legal? He is threatening to fire me....I am a Iraq Combat Veteran, I am insured I guess through the VA, technically not insured I guess, I just get much lower "free" benefits from the VA. Apparently if I don't enroll in the company's group health plan, or at least disclose this info to their group health insurance they do not qualify for the next "group discount" or something along those lines.

There's other problems that this employer is doing such as in a staff meeting telling everyone they aren't allowed access to their employee files. I have a e-mail to the officer manager asking for my file, along with numerous attempts verbally. is this illegal?

Also up until this last weekend employer hasn't paid overtime to any of his employee's ever, this employer has been in business for 10 years, has had anywhere from 1-10 employee's at a time, with a majority of them pulling weekend,holiday, and overtime work, while only receiving normal rate of pay.

Last major issue, at least to me, there could be other issues as well i'm not completely sure of my rights. The last 2-3 receptionist's we've had have been female, young, attractive, and have been given varying amounts of "extra benefits" such as flying one receptionist to Reno, or Las Vegas to have her teeth worked on, the owner of the firm I work as paid for tickets for both the receptionist and her mother, to one of the above mentioned places, paid for the dental work, and hotel stay for the weekend, and the flight back. Same thing with 1 possibly 2 other receptionists, but local rather then Vegas or Reno.

The owner will frequently use obscene language when yelling at his employee's, along with other threatening, and vulgarities. I work at a Law firm, dealing with personal injury, and workcomp. The owner is a multi-millionaire who believes he's untouchable. Please help.