Thanks folks. I'm consulting with a lawyer this afternoon (I will not file, but I need to know what things I can do to protect myself financially since she is now being vindictive with money). I will also talk to them about splitting up the car and our son.
I know it sounds crazy, but not a single member of my wife's family agrees with her and they have actually agreed to testify in my defense if it turns into a custody battle. My MIL is trying to convince my wife to come and stay with them for an extended period of time, both to try to get her out from her uncle's influence and to see if she can get her to listen to reason. I'm not sharing too many details with them but they are 100% supportive.
My family is a great support, and I will be trying to see if I can convince my wife to let me take my son up there, even just for a week, to both get away from the situation and to give us some room apart.
My wife came over, and I dropped her back off at her uncle's house this morning, I'm keeping the car and our son today and tomorrow. We didn't talk much, and haven't talked since. I'm crushed that she turned into the exact opposite of anything she ever was before.
I'm not taking any bait, even when her uncle got in my face and pushed me I didn't even raise a hand because I knew that if I did it would reflect badly for me.