Hi Shoaib,
Scaley face mites will cause beak deformities and can cause permanent damage and if left untreated, the bird will eventually die. It is best to take all of the birds to an avian vet for treatment. The home remedies are not effective. Before you put the birds back in the cage, it needs to be thoroughly disinfected with a diluted bleach solution or other disinfectant, throw away anything made of wood or rope, including perches, and replace with new perches and toys. Only the plastic and metal items are safe to keep after being disinfected. Rinse everything well before you put the birds back in the cage. You can also ask the Vet to recommend a disinfectant. The birds may require more than on treatment to get rid of the mites completely.
Thank you for asking Lafeber,
Brenda