"In 1922 Lenin had a stroke and was forced to stop political work. He continued writing and even wrote significant works such as “On Co-operation” which argued in favor of the possibility of building Socialism in one country. However his condition deteriorated, he had another stroke and was confined to a wheelchair. He still tried to keep in touch with politics and dictated several letters and other documents until he eventually lost the ability to speak.
But what is this about rudeness? Stalin was made responsible of Lenin’s health by the Central Committee (Stalin, Trotsky, Dzerzhinsky, Kalinin, Molotov, Bukharin, Zinoviev etc.). The doctors ordered that Lenin was not to be involved in politics because he had to avoid stress. He was also prohibited from reading political documents.
Lenin didn’t like it one bit although he jokinly said to Stalin:“I am not allowed to read the newspapers”,”and I must not talk politics. I carefully avoid every scrap of paper lying on the table, lest it turn out to be a newspaper and lead to a breach of discipline.”
(Comrade Lenin on Vacation, notes)
As his condition worsened he grew agitated and frustrated. Stalin was constantly there making sure he wasn’t doing political work. Lenin eventually asked his wife N. Krupskaya and his sister M. Ulyanova to start smuggling him political documents which they did against the doctors orders. It is quite probably that this is the reason why Lenin was agitated with Stalin and probably emotionally unstable due to his severe condition.
Note that the part where Lenin criticizes Stalin’s rudeness was a later addition to letter II. In the original later he said nothing about Stalin’s rudeness. Having known Stalin for years it seems odd that he would suddenly become so concerned about his manners unless it was because of his illness.
I think its worthwhile to hear the opinion of Lenin’s sister Maria:
“There was an incident between Lenin and Stalin which comrade Zinoviev mentions in his speech and which took place not long before Ilyich lost his power of speech (March, 1923) but it was completely personal and had nothing to do with politics. Comrade Zinoviev knew this very well and to quote it was absolutely unnecessary. This incident took place because on the demand of the doctors the Central Committee gave Stalin the charge of keeping a watch so that no political news reached Lenin during this period of serious illness. This was done so as not to upset him and so that his condition did not deteriorate, he (Stalin) even scolded his family for conveying this type of information. Ilyich, who accidentally came to know about this and who was also always worried about such a strong regime of protection, in turn scolded Stalin. Stalin apologized and with this the incident was settled. What is there to be said – during this period, as I had indicated, if Lenin had not been so seriously ill then he would have reacted to the incident differently. There are documents regarding this incident and on the first demand from the Central Committee I can present them.
This way, I affirm that all the talk of the opposition about Lenin’s relation towards Stalin does not correspond to reality. These relations were most intimate and friendly and remained so.”"