I'm really worried about my friend. His oxygen level is around 90 when he's on 2L of support, but it drops to 55 when he tries to sit or do anything active. I know he had corona, and his CT score was 1424 on May 7, 2021. They've given him remdesivir, and he seems to be recovering from the virus, but he's having trouble breathing when the oxygen support is removed. It's been a month since he tested positive for COVID, yet he still needs oxygen. He recently had another CT scan on May 28, and the score is up to 2124. Can you help me understand what's going on with him? Why is he still facing these breathing issues? He's still in the hospital, and we're just really concerned.

his CT score has increased that means his infection is increased. that infection needs to be reduced then only he can be without oxygen support