The safest investment in the United States is Treasures. The Federal Reserve just increased the short term rate for the first time in about seven years. But the banks are under no obligation to increase the rate they pay. So you (or rather they) can loan money directly to the United States Government by buying Bills, Notes, or Bonds. To do this you set up an account with Treasury Direct. You print off a form (available at the website) and take the filled out form to the bank. At the bank their identity and citizenship will be verified and the bank will complete the form. The form is then mailed into Treasury Direct.
There are at least two investments you can make at Treasury Direct that guarantee a rate of return better than the inflation rate. They are I-series bonds and Treasury Inflation Protected Securities (TIPS). Personally, I prefer the I-series bonds to TIPS.
Here is a link to the Treasury Direct website for information on I-series bonds. this link takes you to information on TIPS.
Edit: To the best of my understanding, the Federal Reserve has no ability to set the rate for notes and bonds. It is my understanding that they can only directly control the overnight rate. Which is the rate the banks get for parking their money with the Fed overnight. I believe that the rates for longer term instruments are set by the market and are not mandated by the Fed (or anyone else in government). It is only by indirect influence that the Fed tries to change long term rates.