I am surprised there haven't been more responses to this. I have noticed that some threads get lots of replies and others very few.
A couple of things bother me here and this is because I am also a grandma and there someone involved in my grandchild's life we could label a narcissist- someone with a load of issues she will never address and has been very difficult to deal with, to say the least.
First of all how to you teach young people respect? Such an interesting question but my answer will be you can't. These things can only be learned. Respect is learned by mutual example, and disrespect the same. It is hard, I would say impossible, to respect someone who disrespects you.
Sometimes respect gets confused with obedience- that we think people respect us if they do what we ask, but this also isn't the case. Expecting respect in this way is corecive and controlling behaviour, and we can only feel respected if the choices we make are supported by those we love.
This kind of coersion, control and manipulation is often found in people we label narcissists, and it will cause distress in families if those basic freedoms children should enjoy as they get older are compromised by this kind of behaviour.
Encourage your grandchild to be themselves- to feel confident about who they are and show them love and affection and be open to them about their worries. Don't disregard their negative feelings, but accept that we all have them, and it is normal to feel bad about things they are not responsible for the choices adults around them make.
Take your eyes and attention away from the step-dad and work on your own relationship with the child. It is so easy to get dragged into the drama these controlling and damaged people make. They are not so powerful as they think they are.
Be your loving caring self and set that example so the child needn't be taught respect, but will show it by also being themselves.