Hardest thing as a parent is cutting ties and letting them soar on their own.
It appears that is what your DS wants. Relish that fact.
I get you want to feel closer to him regarding his future, but as a Mom that now has a college grad, a DD 2014 (college) and a 2016 child, my perspective has changed over the yrs.
It is DS's life, and I must remember he is 22 yrs old, he is no longer the child. I must respect that he will not include me in every aspect of his life. My investigating, will soothe my nerves, but if I use this information for a dialogue, I need to be prepared to feel his wrath.
Trust me, he has shown his wrath. We get it...his life, his journey. Our job is to shut up and color!
FWIW, I chuckled at the manual phone thing. Bullet and I never saw manuals, orders, etc. We got a phone call where he said I need to get shots, buy X.Y.Z. and drop me off at the airport on this date. I only assumed the phones would be confiscated.