If your wife is letting them at you in your most vulnerable time, a gun is not going to do much if it is put away properly. Having a kid is a good reason to store it properly.
Friend, I am so unnerved hearing this. I do not know you in person, but we enjoy some of the same things in life. You are absolutely astonishing. To fight side-by-side with your son, and WIN, against attackers who had inside help.... Truly amazing.
You two have a bond of brothers as well as father-son. You have proven to your son, that together, you can do anything.
He will be looking to you to see how to handle the rest of what is coming up. Don't worry about letting him see your emotions. And when it comes to trial time, show him what you do to people who attack you and your boy.
Keep an eye on the little guy. Adolescence is a trying time as it is, and when you find out your mother has gone crazy, it will not make it easier.
Keep the lines of communication open and urge honesty. Put that woman away.