Be Civil when responding to THEIR inquiries. Do not offer up anything unless asked. RESPOND. Do not initiate. This way they cant complain you are not providing asked information you are just forcing them to ask instead of them relying on you to always provide on your own. Not your job anymore. I know your MIL is in what she perceives to be the middle but she has her own mind doesnt she? You have never made her feel like she cant call you. You have been gracious. You have done enough for these people.