Sorry to hear about your case (or that of your husband). I doubt that you will get a direct response from CIC or the visa office. You have responded to what they asked. Since the Background, as you mentioned, is already showing "In progress", the VO is in fact, continuously processing the application which is a good sign. You have sent them all the proofs that you have that the mother of the child is pretty obvious will not cooperate. Let's hope and pray that the VO will be convinced (to which I am sure they will). Just be prepared though, that your husband might get something from them for him to sign or for him to confirm and agree that he will NOT AT ALL be able to sponsor his child in the future. In any case, you both should keep all the evidence that you have so that if and when the time comes and his child is grown up or something happens to the mother, that his child will then know the reason/s why he cannot sponsor him/her.
All the best to your application! If you don't mind sharing your timeline, please?