They do tend to obsess over the age and looking and acting young. They moods are up one minute and down the next. It's difficult to determine how they'll be at any given time. All you can do is just listen, step aside when they are nutty and allow them to think about things, including that "mirror, mirror, on the wall who is the fairest of them all" period of time each day.
He's trying to figure you out. You aren't reacting/responding the way that you use to and he's puzzled by your changes. That's okay...it's good for him to inquire and mull things over.
Now, it's going to be something when your family comes for a week and then your niece is coming to town too...that will be interesting. If she asks questions, be honest to a point, and if the questions are too much for you to handle, just say, it's a work in progress and hopefully things will settle down in the future.
I don't think I would mention the niece coming until closer to the time. Why? Because her plans may very well change.
The next month or so is going to be stressful in your household. Plan to have some activities that will help you and your sons when dealing with the stressors.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
