Let's say I am single and file and suspend for SS benefits at full retirement age. If I'm diagnosed and given three months to live at age 68.5, can I receive a lump sum benefit back to my FRA? or is the lump sum only payable back 6 months?
For people who voluntarily suspended their benefits prior to April 30 2016, the answer is yes. But, the answer is no for people who suspend their benefits on or after April 30 2016 (https://www.ssa.gov/planners/retire/suspendfaq.html).
And, if you file for and suspend your benefits after April 29 2016 as opposed to simply not filing, you could not even claim 6 months of back pay. The earliest that you could reinstate payments in that event is the month following the month of your request. On the other hand, if you simply waited until age 68 1/2 to file for benefits you would have the option of claiming up to 6 months of back pay.