A wrongful death case can be brought by a certain class of persons based on how they are related to the deceased person.  Under Missouri law, the surviving spouse, children, mother and father of the deceased all have the right to file a lawsuit.  If a child of the deceased person is also deceased, then the deceased child's children may also bring suit. All of these people have the right to bring a joint lawsuit.

If there are no persons in the class listed above (no children, spouse, mother or father of the deceased), then a brother or sister of the deceased can bring the claim.  If there are no brothers or sisters, than the law should be consulted to determine whether anyone has the right to a cause of action for the wrongful death of your friend.