Excuse me, there is no video and no other donors came forward with that story.
Incredible claims require incredible proof.
And George W. Bush doesn’t usually say anything negative about anybody.
Others are finding the story credible, and it is spreading. It could easily be denied, but...
“Freddy Ford, a spokesman for George W. Bush, did not deny that the former president had made the disparaging remarks about Cruz when asked to comment by Politico.” From:
http://www.foxnews.com/politics/2015/10/20/george-w-bush-reportedly-rips-ted-cruz-to-jeb-bush-donors/
http://www.redstate.com/2015/10/19/george-w-bush-attacks-ted-cruz-advantage-to-ted-cruz/
http://www.mediaite.com/online/george-w-bush-is-reportedly-no-fan-of-opportunistic-ted-cruz/
http://www.americanthinker.com/blog/2015/10/why_george_w_bush_dislikes_ted_cruz.html
So, until Dubbya or his representatives can do more than ‘not deny’ the assertions, it would seem that they stand.