In Michigan a no-fault (PLPD) policy includes personal injury protection (PIP), property protection (PPI) and residual liability insurance (BI/PD).
Personal injury protection benefits normally will be paid even when a family member is a passenger in another person’s car or is a pedestrian when an accident takes place. The personal injury protection coverage of your no fault policy also covers anyone who does not have a no fault policy and is hurt as a passenger or pedestrian in an accident involving your car. It will also cover a motorcyclist who is hurt in an accident involving your car.
So you should contact your agent to see if your daughter's injuries would go through your PIP policy as it would appear they should unless she has her own auto insurance policy. Other passengers, if they have their own auto insurance policies with PIP, would contact their own insurance providers (or parent's) as well.
Since your daughter's boyfriend does not own a vehicle and thus does not have his own insurance policy, he should see about making a PIP claim through the car owner's PIP policy.
If no PIP is available or applicable then the at-fault driver's Bodily Injury Liability would be used to cover the bodily injury claims.
Your agent may be able to give you more information on the situation and how claims should be made. Beyond that you can also contact the insurance regulator for Michigan, the Office of Financial and Insurance Services (OFIS). The OFIS can be called on their Toll Free number 877-999-6442.
If you have a policy through CarInsurance.com, any of our claims specialists can help you.