Mentoring and discipling are not the same things.  The terms are not interchangeable.  Although disciple making, like mentoring, takes place in this world, it also engages a just as real spiritual dimension.  Paul writes:

For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms. (Ephesians 6:12)

You will encounter satanic activity in the life of your disciple.  If Jesus allowed Satan “to sift Peter as wheat” (Luke 22:31), what makes me think that Satan will not test my disciple?  (When I use the term “Satan”, I am not suggesting that your disciple will encounter Satan himself, as did Peter.  What I do mean is an encounter with evil spiritual beings that, along with Satan, make up the “dominion of darkness” (Colossians 1:13) and what Paul calls “spiritual forces of evil in the heavenly realms.” (Ephesians 6:12)

There are times when your disciple’s attitude and behavior can only be explained by the influence of an outside evil force.  I am not suggesting that every sin, every failure, or every attitude is linked to satanic activity, but we do need to be open to the possibility that evil beings may be at work in my disciple.