what does the last sentence mean?
【The substance of the meeting—their final conference together—is unclear. According to Johnson's recollection nineteen months later, "There definitely was not a disagreement. . . . There was an active discussion" in which the two "were in substantial agreement." He did not define the nature of the discussion, but if the memories of others are to be credited, the President and his successor had words over the state's political feud. Precisely what was said is unknown, for one President is dead, and a whirlwind was about to descend upon the other, blurring the sequence of events leading up to it. 】

1.I wonder what does "a whirlwind" indicate to?"
2." blurring the sequence of events leading up to it." does "events"here indicate to the result of that last meeting? then, what does "it" mean? I am not quite sure what exactly does it leading up to?

Question

what does the last sentence mean?
【The substance of the meeting—their final conference together—is unclear. According to Johnson's recollection nineteen months later, "There definitely was not a disagreement. . . . There was an active discussion" in which the two "were in substantial agreement." He did not define the nature of the discussion, but if the memories of others are to be credited, the President and his successor had words over the state's political feud. Precisely what was said is unknown, for one President is dead, and a whirlwind was about to descend upon the other, blurring the sequence of events leading up to it. 】

1.I  wonder what does "a whirlwind" indicate to?"
2." blurring the sequence of events leading up to it." does "events"here indicate to the result of that last meeting? then, what does "it" mean? I am not quite sure what exactly does it leading up to?

Answer

Hi! A whirlwind is a quaint word for a tornado. Here it is a metaphor for the many overwhelming events that occurred to Lyndon Johnson as soon as he was required to step into the presidency when Kennedy died. The whirlwind make Johnson forget some of the details that immediately preceded this onslaught of major events that engulfed Johnson.

Okay? :)

Answer

One president was dead and something bad was about to happen to the his successor. Since none of them were alright, they could give no account later of what led to this trouble. As a result, no one really know what was the sequence of events that led to the whirlwind.

"It" refers to the whirlwind (i.e. trouble). "Events" signifies the think that lead to the trouble that descended over the president later.

Answer

A whirlwind is any event that happens at great speed, with great confusion and is very dramatic.  An actual whirlwind would through physical objects around - it would be fast, dangerous and confusing.
If you were trying to remember something that happened months ago while something important happened to you currently (a car accident, for example) you would have a much harder time recalling the event - it would be blurred - confused.
The whirlwind they are talking about is the Vietnam conflict, which was to shadow the presidency of Johnson.  Compared with the Vietnam conflict, a minor state political feud would be unimportant.

Answer

A whirlwind (something like 旋风) - here the meaning is not about the weather but about this man's life, or the things that were about to happen in this man's life. He was a president. So he was to experience, or America was to experience turmoil or 动荡. The mid 1960s

So then.....because of all the unrest, or turmoil or disturbances that happened when this many became president, he would forget or his memory would become blurry  模糊 - "it" is the meeting described between the two men. Because of the unrest, Johnson's memory became blurry, or confused about the steps leading up to their meeting.