Stay by their side and stand up for them if they allow you to step in. Hang out with them especially during times that they have problems — like lunch or free time. Bullies often bother people when they're alone. And having people to hang out with can help them feel confident and accepted. Be willing to listening an be understanding.
I'm sorry but could you ask the question more specifically? It does not make sense reading it out now. :) I would be happy to help if written more clearly though!