Hang in there CrazyGuy. You're in a tough situation. Your spouse is really working hard to get your kid(s) in the truth and is convinced that having them baptized will lock them in so to speak. In my opinion the key thing for you to do is love your son unconditionally. It may make you physically sick to see this happen but if you stand by him whether or not he gets baptized he may see the light one day and knows that you will be there for him. A lot of us never had that from a parent.
It seems like you are doing all you can. My oldest told me several years ago that she was going to get baptized. When I asked why she admitted it was to make mom happy. I told her that baptism can't be undone and that she could get disfellowshipped if she makes mistakes in life and that she can't change her mind. She said she could change her mind just like I did. As a kid she had no idea how hard fading was and that I wasn't actually free to just speak my mind and change how I felt without walking on eggshells.
So, perhaps ask your son about disfellowshipping or the fact that Jehovah will destroy 99.99% of everyone on the planet. See if he has thought of those things and how they affect him.
I was able to get my daughter to agree that she would wait until she was 18 to get baptized. She isn't a witness. In fact she called it a cult several times over the past couple months and wants to know how we can get mom out.
Feel free to PM anytime.