Information is absolutely paramount in order to understand what has happened. According to media reports following a plane crash, for example, a great many people have been troubled by the survivors' needs to fly over the crash site, see their loved ones' bodies, stay in the area waiting for news, or ask detailed questions about the crash and the investigation. Yet this is absolutely normal. Please give survivors as much information as you possibly can. It is tremendously healing.
Bereaved survivors are their own best experts.
Bereaved adults are traumatized, they are not mentally ill. They know what they need and they know what they can handle. Generally, survivors will not seek information they don't want to receive. Furthermore, the various chemical changes that take place when one is severely traumatized serve to protect and shield the survivor from a pain that would probably, and quite literally, kill some of us if we had to experience it unprotected. An important rule for helpers is predict and prepare.