In the United States if someone is "brain dead" from an accident, the family is approached for organ donation. If anyone in the family is opposed, they won't do it. You may be an "organ donor" on your driver's license, but that is not a legally binding contract. It just shows your wishes.
I have heard than in some countries there is "Presumed Conscent," which means it is "Presumed" that everyone if put in that situation is an organ donor unless the family specifically tells them they don't want the body to be used for organ donation.
Do any of you know what your country's policy is?