Here are the reasons that you received a redacted SSN application (the "120-year rule) for the person whom you're researching.
* The date of birth for the deceased must have occurred at least 120 years ago.
* The parents of the deceased must also be be deceased.
* If 120 years have not passed since the deceased person's birth date, then you must provide proof of death to the SSA for both parents of the deceased. Otherwise, the SSA will redact the information from the SSA application in the interest of privacy of one or both parents who may still be alive.
SOURCE: GN 03350.005 Freedom of Information Act Requests: I. SS-5 Requests Involving Extreme Age, https://secure.ssa.gov/poms.nsf/lnx/0203350005