If in an accident with unlicensed driver using friend/owner's insured car, what is the friend/owner's  insurance company responsible for?

You may have benefits available to you under your own Mass insurance policy. They are referred to as uninsured/underinsured motorist coverages.

If you get your insurance in Mass ( and maybe even if you don't), you may also have PIP (Personal Injury Protection) benefits available to you, usually, up to $8000 (unless you waived this coverage to save a few dollars - very bad idea BTW), for medical expense and lost wages. These coverages, and your property damage loss, are customarily referred to as first party coverages in that they protect you directly as opposed to protecting third parties who you might inadvertently injure.

The owner of the car may well be liable.  and as Ted said, your own insurance coverage can apply.

If you need assistance, contact me 978-749-3606

You should speak with a lawyer right away.  The owner of the automobile may be liable if the person driving the car was authorized to drive it.  You should also check under your own policies under/un-insured motorist protection.  You need to provide notice right away if you are going to claim such benefit.

Best of luck in your recovery 617-357-4898.