My father passed away in 1992. My mother is 78 and never received survivors benefits that she believes she is due to her. Is this something that Social Security automatically does for her or she needs to apply for. And if she needs to apply can she still apply after all this time has passed?

Your mother should call or visit the SS office and ask how to proceed. Here is some useful info for you (and her):

Social Security Online: Widows, Widowers & Other Survivors: Qualify and Apply (http://www.ssa.gov/ww&os2.htm)