I recently engaged with a JW regarding the official understanding of a ‘generation’ and unfortunately he didn’t have an answer to the points I was making. I was left a little confused as to what the official JW response would/should be.
That is typical nowadays. Most adult JW's in the 70's through the 90's who studied at all could answer questions about the doctrine. And it's not really that the JW's later were not as sharp, but the doctrine started changing so much and was so goofy that many didn't bother to keep up with the chariot.
Despite my never accepting it, I can at least explain it, like a good JW should be able to do.
The short story- There was a group of JW's alive in 1914 whose lives significantly overlapped with JW's later, and without any reason whatsoever (other than that time is up on their old doctrines), they are saying the two groups are one big overlapping generation, and the end will come before the second group passes away.
Basically, my great grandmother died at 103 and I was an adult before she passed, so our lives overlapped significantly. Despite her being 60 years older than me, the 'overlapping generation' crap says that my great grandmother and I are of the same generation.