If you followed that last line of reasoning and tend to agree, then you might also be lead to the conclusion that death (and we do mean bodily death this time) is in fact something of a good guy.
It's Ivan's fear of bodily death that forces him to re-examine his life. With the prospect of his death before him, it's impossible for Ivan to continue living falsely. In the end it's the confrontation with death that brings Ivan to the thought that maybe he's lived wrongly. This conclusion is just what he has to recognize in order to fully live. That's a good qualification for a mentor, right? Of course, it's questionable whether Ivan completes the process of realization on his own. God seems to step in at the end to help him. So maybe we should say God's a mentor too.