I am sorry this needed to happen, but it sounds as though it was necessary.
The staff will be very aware of his needs. they are very experienced.
Usually throughout the day they are very structured. Many of our kids find this to be very comforting and they feel safe because they know exactly what will happen at what time. I have heard from parents here that kids are often scared to come home because it is not as regimented/structured.
If he is not calling, and when you visit/call he is not panicked/anxious, then he is probably doing fine. Often kids will not want you to leave (bar the door, etc...) but a few minutes after you are gone they are into an activity and just fine.
Keep talking to him during the approved hours. Visit him on visiting days. Talk to the docs and STAFF. My son was much older when he first went into the psychiatric hospital but I made allies on the staff and learned what he reallly was doing and saying. This helped me make medication decisions and other decisions.
I think I started it with a plate of cookies for the staff. Nothing major, they thought I brought 2 dozen cookies for my son (EEKS - that much sugar and he would have been meaner than a momma bear who's cub disappeared!). When I got them to understand the cookies were for the nurses and interns, they were just shocked. After that I got real info when I called. It was good because the psychiatrist on staff spent less than 10 mins a week with each kid!!! The nurses and social worker therapist were the ones who knew what was going on.
Whatever happens, I know it hurts your mommy heart to have your baby in the hospital. Be kind and gentle to yourself, take time to recharge yourself and your marriage - even if it is just comforting your spouse in the evening.
Sending gentle (((((hugs))))) for you and husband.