A seeker wrote….
Another interesting time-based shloka – Book 12 Chapter 51
14 पञ्चा शतं षट च कुरुप्रवीर; शेषं दिनानां तव जीवितस्य
ततः शुभैः कर्मफलॊदयैस तवं; समेष्यसे भीष्म विमुच्य देहम
My rudimentary sanskrit says – Krishna tells Bhishma that he has another 56 days to go?
This occurs on the 2nd day after the war is over, when all the kuru folks and krishna go see Bhishma. According to Achar, war started on Nov 22 and bhishma died on jan 17. As we say in tamizh, engeyo idikuthe or does not compute in english.
If you have access to copy of my book (Kindle or paper), refer to pages 131-142,where I document and discuss 23 chronological references from the Mahabharata text, in the context of Bhishma-Nirvana.
The above verse (quoted by you) is indeed critical, reference 120 in my books (Error Elimination experiments 64-67, both inclusive).
The above reference DOES NOT appear on the 2nd day after the War is OVER!
Rather it occurs after the War is over
+ ~30 days (Pandavas spending on the bank of Ganga, before returning to Hastinapur)
+ few more days (X, where X = 1, 2, 3, 4, 5, 6 or 7 but not more than that).
At this time, Krishna asks Yudhishthir to go and see Bhishma. They all go back to Kurukshetra.
This is the time when Krishna states to Bhishma that the latter has 56 more days to live.
Bhishma Nirvana and related references from the Mahabharata text, alone, are capable of falsifying almost all (96%+) proposed years for the Mahabharata War, i.e. Any and all claims for year of Mahabharata War that fall after 4000 BCE.
That is the subject of my ongoing project.. Bhishma-Nirvana.
Of course I covered it all in my first book. And while good number of readers understood the explanation, majority have missed the amazement and wonder of this evidence for the history of India.