Isn't it weird that during one of the most traumatic times in our lives so many other crappy things happen? Sometimes I used to think that God had to keep whacking me with bigger and bigger things to get me to pay attention and focus on what was truly important.
Pain is inevitable, suffering is optional or so my brother told me. We all make choices in how we view the world; from the standpoint of a victim, of being content in ourselves, fear, belief.. whatever myriad of perceptions pop to the surface.
With your son you made a very difficult decision made out of love and with his best interests at heart. The good thing about having momentum is its flexibility. If it doesn't work, the plan can be altered. The beauty your son shared is heart warming. Since he is so perceptive, have you asked him what his thoughts are about the plans?
Letting go is tough, as I learned when our first went to college. At the same time I understood what drove a mother bird to shove the no longer fledglings out of the nest. When it's time to leave, to stretch out those wings, let them fly. If they don't respect the nest, shoo (well with dorm life as the alternative.).
But letting go of a tween is letting go of the last visages of childhood. I found that focusing on blessings rather than losses helped bridge the transition. If it's the right thing, it will work. If it isn't, you will all know. And love will be your guide.
You have a deep thoughtful soul. Try to let the tide pull away regret and allow all the beauty and compassion to flow.
About your younger son.. it's at your wife's discretion if she allows communication with your little boy. You have no control over that as hurtful as it is. Whatever you say to your wife, about having the two boys together with you before you oldest leaves, keep it simple, factual and short.
