That was four years ago. In retrospect she has indicated that she should have stayed at home because it was much easier. She's had regrets about giving up the life of a dependent child and becoming an adult too soon. I think once all the financial demands became more stifling she realized what she had gotten herself into. Now, however, she is functioning very well at 22 and hasn't had our financial support for three years (except for health insurance), and she is way ahead of the financial and independence curve compared to most others her age. Despite the awkwardness and the abruptness of her exit, the end result is good. You may not be able to step back and understand the outcome of this abrupt departure and transition till much later either.
With regard to your last question, I'd vote for giving him some space. When you back off, it frees him up to come to you without pressure. He may read any contacts you make as putting pressure or guilt on him, even though that is not your intention. When regular family gatherings are planned, you can reach out, but otherwise I'd give him what he seems to want now. I feel that I chased my daughter too much after she left. If I could do it differently, I'd have given her more space early on and let her come to me.
I'm sorry that I can't relate to having such a large household and no free time. My husband and I only have 2 AC and are finally empty nesters, at least for now. Eventually I suppose we all have to find some outside activities to give our lives meaning, but for now in your family there are others who you can choose to focus on and create special memories.
All the best!