covid and horrible

my son has covid and he sound bad i had it last week it's going around the household i've cleaned washed everything sprayed lysol everywhere and it's still going around. my son cough and head clogged he sound bad. i'm giving him vitamins nose spray advil i need to get him cold meds i ran out. i tryed onion recipe... anything i can do?? have humidifier going but it's small and probably not going work.