I was asked to tutor siblings together a few years ago, although they were at secondary school. As the conversation unravelled, it became clear I would be a babysitting service as the parents would want to go out. Also, when I asked about the children's current performance at school, I was told that it wasn't relevant to the tuition. I turned the work down. Explore exactly why he wants them tutored in a group, and why not tutored individually for 30 minutes each, for example.