Hi my father is admitted in hospital due to severe covid pneumonia for more than 20 days his saturation was nor normal when admitted with lot of chest infection was on artificial oxygen since these all days he is okay now he will be discharged in few days I wanted to know what precautions in future we should take and is air purifier or humidifier a good option to buy will it help him getting his lungs cured up from current infection or they are just for attracting ppl? Thanks.