Where is your evidence for this because he does not want to run for President. He still have the appetite for his job he just does not want the Presidency and no one could have had more vigor than Lynne Cheney on the campaign trail last year.
The most recent photo I have seen of him taken on 17th February hardly seems that of a tired ill old man.
Met with him in Orlando during campaign. He was VERY tired. Plus, he has nothing to prove.
Seriously, he will be glad to go home.