Margaret, profiles of persons deceased less than 100 years ago are not required to be open. They can be open, public, or private at the discretion of the profile manager. In this case, the person died in the 1980's and the profile manager has made both the family tree and biography public.
If you have information to contribute to it, you can add it as a comment or send a private message to the manager. Either way, be sure to add sources for the information.