Here are the relevant Watchtower quotes showing their New Light on the possibility of people repenting and supporting the Anointed during the Great Tribulation:
Watchtower, March 15, 2015, Page 27:
This judgment will occur toward the end of the great tribulation just ahead. And what of the reason why people will be judged as either sheep or goats? The outcome hinges on how they have treated the remaining ones of Christ’s spirit-anointed brothers on earth.
Watchtower, July 15, 2015 Simplified Study Edition:
In a similar way in the future, when the attack against Babylon the
Great is “cut short,” we cannot expect that many people will suddenly
convert to true Christianity.
Watchtower, July 15, 2015 Regular Study Edition:
Should we conclude, though, that the
destruction of the religions of Babylon the Great results in the death
of all the former members of those religions? Apparently not. The
prophet Zechariah was inspired to write about that time. Speaking of
someone who was previously part of false religion, the account states:
“He will say, ‘I am no prophet. I am a man cultivating the soil, because
a man
bought me when I was young.’ And if someone asks him, ‘What are these
wounds between your shoulders?’ he will answer, ‘Wounds I received in
the house of my friends.’” (Zech. 13:4-6)
So, apparently, even some of the clergy will abandon their religious
course and deny that they were ever part of those false religions.
[...] What will happen after the destruction of false religious organizations?
It will be a time to reveal what is really in our heart. The majority
of mankind will seek refuge in human organizations that are likened to
“the rocks of the mountains.” (Rev. 6:15-17)
Figuratively speaking, however, God’s people will flee to the refuge
that Jehovah provides. In the first century, the interval was not a time
for a mass conversion of Jews to Christianity. It was a time for action
and obedience on the part of those who were already Christians.
Similarly, we cannot expect that the future interruption in the great
tribulation will result in an influx of new believers. Rather, it will
be an opportunity for all true believers to prove their love for Jehovah
and give their support to Christ’s brothers.
[...] Although
we do not fully understand all that will happen during that time of
test, we can expect that it will involve some measure of sacrifice.
