Humans, if I can generalise, need to feel safe and secure, including men, lets be honest. If a human is becoming less emotionally honest, its normally because they can sense that something isnt going well, and the very basic need for any human is self preservation, be that physical, emotional, psychological. It sounds like she is possibly not being emotionally honest as she can sense things are not going well and withdrawing to protect herself. I do the same myself with the wife due to my current issues. I push her away because I believe, rationally or not, that she is a threat to me psychologically and emotionally. This isnt the case, shes a great girl, but thats the thing about irrational thought processes, they make us believe things which may not be true. Luckily for me, my wife is incredibly stubborn so she stays with me, poor girl.
I like writing letters to the wife, and she sometimes writes her response back to me. The beauty of this is that you can take as long as you long to write it, you can phrase it how you like, explain yourself in a way which may not be possible face to face, because, lets be honest, once an argument starts, all ability to correctly and rationally explain your point of view or concerns go out the window, especially if you are trying to show an emotional perspective. Argument starts, our ability to explain our emotional state or concern vanishes as we now feel threatened by the argument. It also alleviates the pressure from her to respond to you straight away, so if she gets angry, she cant suddenly retaliate with something on the spur of the moment because you arent there. I wrote one to my wife a few weeks ago saying how much I am struggling with life and I dont want to be here anymore. When I got home from work, she opened the door with tears in her eyes and just gave me a massive hug and we chatted for hours - she wasnt aware of how much I was struggling even though I had verbally told her a few times.
Be kind to yourself, and be kind to your wife. It is so easy to find fault and blame when both parties are suffering from loss, but remember, she is also suffering as well and she needs support as well. I imagine its scary for her to lose her son, and in her mind, possibly her husband as a result. Communication is absolutely key - it doesnt have to be verbal communication if its not possible at this stage, but communication. Also trust - once trust is gone, any relationship is doomed. Its a massive structural component of any relationship - plutonic or otherwise.
Oh, Ricky, when was the last time you just put your arms around your wife for no reason and just told her you loved her. That is something which us men often forget to do, but its a really simple thing with a massive benefit, for both of you.