You might try to help him see your viewpoint this way by helping him to understand that he Watchtower had no other choice but to admit their “mistake”. When you predict that the end will come in 1925 and it does not happen, what other choice do you have? You must admit you were wrong. Rutherford admitted after this debacle that he “made and ass of himself”.
The problem is he did not just make himself look bad. He brought ridicule and dishonor on God’s name. Here are some of the predictions he made just about 1925:
1922 "This chronology is not of man, but of God. Being of divine origin and
divinely corroborated, present-truth chronology stands in a class by itself,
absolutely and unqualifiedly correct...." (Watchtower, July 15, 1922 p. 217)
1923 "Our thought is, that 1925 is definitely settled by the Scriptures. As to
Noah, the Christian now has much more upon which to base his faith than Noah had
upon which to base his faith in a coming deluge." (Watchtower, p. 106, March 1, 1923)
1924 "The year 1925 is a date definitely and clearly marked in Scriptures, even
more clearly than that of 1914. (Watchtower 1924, p. 211)
Then by 1925 he starts hedging his bets by blaming Satan for what he previously said was “of God”
1925 "It is to be expected that Satan will try to inject into the minds of the
consecrated, the thought that 1925 should see an end to the work." (Watchtower,
Sept. 1925, p. 262)
In the scripture in question Paul was warning about this very thing. He said
“not to be quickly shaken from YOUR reason nor to be excited either through an inspired expression or through a verbal message or through a letter as though from us, to the effect that the day of Jehovah is here.”
Paul here is warning that there will be people who claim to be apostles (or who claim to speak for God) that will give “inspired expressions” or “verbal messages” that would say that “the day of Jehovah is here”. This is EXACTLY what the society has been doing.
Ask your brother to explain Deuteronomy 18:22. Let him know you are not simply being argumentative but that you sincerely feel that the society is guilty of exactly what is described here. The fact that they admit they were wrong means nothing at all. They had no choice but to admit it.
You could also ask him what he thinks about this quote from Awake!
"True, there have been those in times past who predicted an "end" to the world, even announcing a specific date. Yet nothing happened. The 'end' did not come. They were guilty of false prophesying. Why? What was missing? Missing from such people were God's truths and the evidence that He was using and guiding them.'' (Awake, Oct. 8, 1968)
You could also draw a comparison between Rutherford and Harold Camping. I think any Witness would admit that camping is a false prophet, if they admit that then how can they justify following Rutherford who was just as much of a false prophet as Camping.
If you really want to help him see TTATT you have to ask questions and teach him to really think. Most Witnesses have a good surface knowledge of “proof scriptures”. You have to go beyond that and get him to learn how to think. That is the hard part. I remember reading somewhere once a comparison between question marks and hooks. Use those hooks to good effect and you might have a 1 in 1000 chance of getting through to him.
If you argue a point and come across as bitter or angry to the WTS then you chances drop to 1 in a million. Help him to know you are sincere, you have sincere questions. Let him try to move you by feeling he is helping you. He has to come to his own conclusions, and even when he does there is no guarantee he will act on them. The cost for disagreeing with the WTS is very very high and only the strongest are willing to accept that price.
Good luck.
PS. The question about Jesus being a false prophet - I believe the transfiguration is how that is explained by the WTS. That is the only explanation I know of.
