Hi Kerj,
It is probably for the best that they did not show. If they call again I would just tell them there is no point meeting as you have no intention of being a JW again, as you have come to realise that the WTS is not directed by Jehovah. (unless you think that doing so will affect your relationship with your father.)
Don't let them draw you into any conversation about your reasons. I had elders meetings and discussions, and they forever play in my head what I could have/should have said. It is far easier to let it go and try to keep the religion as far from your life as possible.
Your child has a lot to contend with going through both a divorce and loosing his religion. I have step children and the boy took it very hard when his father left, but he is over it now and happily on with his life. It sounds like you have a good relationship with your son, so that is the most important thing for him. The other important thing is for him to build new friends outside the religion.