Good morning, I would like to help you today.
This sounds like a very frustrating situation, as you need and want to keep the assistance of your housekeeper, but her child seems to make life very difficult for you and your dog. I do also understand that you have pleaded with your housekeeper to keep her son away from your dog, but she fails to do so, or moves too slow to stop him. I also can understand you feeling most responsible for your dog, seeing that the child is not your own; however it does appear that you like him more than you don't; and that this child has developed a liking for you as well. This sounds like a good reason to want to make things better with him, and not just get rid of your housekeeper (and her son). I would be a bit concerned with how it seems your housekeeper is ignoring your request (this could bring up issues of trust). This may be a useful standpoint to come from when you speak to your housekeeper (letting her know that you want to be able to trust her to follow the rules of your home). More importantly, I think that a good way to bring urgency to the situation when you do speak to her again, is to express your concern for the safety of not only your dog, but her child as well. A lot of times, children get bitten by a very kind and playful dog because they are picking with or agitating the dog. Let your housekeeper know that you do not want such a thing to happen with your dog and her child, and so it is necessary that he is not allowed to pick at the dog.
I also thing that it may be helpful to find a dog trainer (who works with people) that can help teach your housekeeper's son the proper way to interact with a dog; this of course would be an extra cost, however perhaps maybe part of the stipulation can be that the payment for the trainer comes (at least partially) out of your housekeeper's pay. Another good teaching tool can be books or videos: "Tails Are Not For Pulling", is one such book that can be read to your housekeeper's son on a regular basis: http://www.amazon.com/Tails-Pulling-Board-Behavior-Series/dp/1575421801
When you are around your housekeepers son, do what you can to teach him what is and is not acceptable when interacting with your dog, and also explain to him that these rules are for his own safety, as well as the safety of your dog: Ask him to put himself in your dog's shoes (paws): "Would you want someone to poke you in the eye or pull your tail?"
I do hope that my answer has been of some help. I aim to provide excellent service; if you feel that my answer is of no help, please message for me prior to providing your rating, so that I can assure that I have done my best to provide you with the answer that you need. Thanks. "earthsister"