EdenOne:
a) The prophecy of Daniel chapter 4 applies solely to Nabuchadnezzar; therefore, the "seven times" are seven years, the exact time that lasted the insanity of the Babylonian king. Daniel chapter 4 contains in itself the prophecy and the narrative of its fulfillment.
That is a logical objection to the claims JWs make about Nebuchadnezzar's supposed 'prophetic' dream.
But it's not the most reasonable conclusion. Since the book of Daniel was actually written in the 2nd century BCE, it's entirely probable that the stories were only loosely based on a 'Daniel' living in the 6th & 7th centuries BCE, and it's possible that the character didn't actually exist at all but was merely representative of some of the captives taken by Nebuchadnezzar as a narrative device.
It's more likely that the story about the dream about '7 times' is really a cryptic reference to the 49 (seven times seven) years from the destruction of the temple in Jerusalem in 587 BCE until Cyrus' decree to rebuild it in 538 BCE. That is much more plausible than a magical man in Babylon revealing a secret dream to Nebuchadnezzar that later came true, without any reliable corroboration whatsoever. This more reasonable conclusion is also consistent with first 7 'weeks' of the '70 weeks' 'prophecy', which apply to same period (despite being later co-opted by Christians with a different starting point), which was the arrival of 'Messiah' (literally 'anointed one'), which Isaiah (more accurately, a later writer under the Isaiah pseudonym) explicitly states was Cyrus.
Whatever the case, neither scenario lends any weight at all to the JW belief.