if it's helpful when dealing with him (as little as humanly possible) maybe act like you are the dreaded recorded phone tree.....Press 1 to ask about the baby, Press 2 to inquire about visitation, Press 3 to comment on the weather.....<<he presses 6>>....i'm sorry, that is NOT a valid selection, Press 1 to ask about the baby, Press 2......
operate from a script and do not waver. YOU select what topics are ok, and which are verboten. and as soon as the very limited conversation drifts off course, you END the conversation. you can even set approved phone times - you may call between the hours of 1 and 3pm. if you call after that, it will go to voicemail and you will get a reply tomorrow between 1 and 3 pm.
i'm not in the least bit surprised that HIS parents are siding with THEIR son. i always caution partners when they think the in-laws have their back....blood is thicker than water. do not attempt to guess what they may or may not be thinking. let their actions tell the story.
and finally, Simon says....step AWAY from the rabbit hole!
it's still under construction (aka he's still digging).