How well did Tolstoy follow his own advice in The Death of Ivan Ilych?
Thank you for the question. I actually like these that combine some literature with history as well!
Tolstoy's personal life (albeit with some commonalities) bears little resemblance to that of Ivan Ilych; however Ivan Ilych offers Tolstoy a chance to expand upon his spiritual philosophy. To this end one can say that Tolstoy was reaching for ascetic morality.
One commonality is marriage. Though Tolstoy's marriage to Sophia Bers was originally happy, later their later life together was very unhappy deteriorating as his beliefs became increasingly radical, such as rejecting his inherited and earned wealth.
Another commonality is belief. Russian-born novelist Vladimir Nabokov has said that for Tolstoy, a sinful life is moral death. As such, death (the return of the soul to God) is for Tolstoy moral life. Ivan had lived a spiritually unfulfilled life, but in death Ivan had entered into a new life.
To the modern reader, perhaps another interpretation of the end of the novella is that of a true consciousness. Ivan has been not a human, but a machine living a lie perpetuated by society at large. It is in his interactions with Gerasim, the servant boy, who is both dedicated and empathetic, genuine human affection is felt. Slowly, but finally, Ivan is able to connect to his family, this is true in the scene when his son kisses his fingers.
Finally, in a connection between fiction and real life, Tolstoy rejected Anna Karenina and War and Peace, later in his life as something not as true of reality. It is this argument supported in The Death of Ivan Ilyich, where family and servants are demanded by Ivan to live honesty, which according to him is more important than water and food.
So, to answer specifically the question how well did he follow his own advice, one may argue that Tolstoy did indeed follow his own advice.
Hope it helps.