It's only disadvantage is radiation exposure but ct scans are part of treatment protocol so can't do much about it

1 year old needing a CT scan for CoViD is rare. Did he have severe breathing difficulty? CoViD what is being seen in kids is very mild and rarely needs extensive investigation. Same for steroids usage. I guess he is reasonably sick to have been advised these. If he is that sick the benefit of investigations outweigh the risk of radiation. I am sure your doc would have explained this in detail.