I went through this with my husband. Besides my intensive research, I also got help and advice from multiple friends who are MDs and Nurses working with COVID patients.

Please do the following for him: Have him lay in a face down (prone position) as much as possible while in the hospital. That helped my husband a lot. (An MD friend told us this is the new thing that helps the lungs recover.) If not face down, at least on his side to allow the lungs to fall forward.

He also must, MUST do the breathing exercises - both exhaling (one device) and inhaling (another device) multiple times each day. If they only gave him one device, request they add the 2nd one. The breathing exercises will keep his alveoli in the lungs from sticking together and healing shut. It may be painful, but he must keep exercising them and inflating them.

He needs to be on concentrated oxygen, anti-coagulants, vitamin C (demand this - either IV or oral), D3 and a steroid to calm his lungs down. See if you can sneak him in some Zinc and Ivermectin pills.

If he is diabetic, have them switch him to injectable insulin to keep the numbers tight and make sure they do a C-Reactive protein test to monitor his blood sugar.

Make sure they do a D-Dimer blood test EVERY DAY to see if his numbers are moving upwards. This is the only test that will tell if he is building those micro clots that don't show up in normal tests. These tiny clots (microthrombosis) will cause all kinds of problems. He needs to be closely monitored for this. If so, he must be on an anti-coagulant, if not on one already.

If and when he is ok to come home, immediately put him on the Ivermectin protocol + vitamin protocol and order home oxygen delivery to give him a portable oxygen concentrator for at least a couple of weeks. Monitor his oxygen at home with a Pulse oximeter and make sure his heart rate, BP and Oxygen is staying in the safe zone.