Ok that is very surprising, but there is more than one way for a bird to lose toes due to necrosis. For example there was a fairly recent thread where a (wild) pigeon lost a foot due to having a rubber band wrapped and entangled around its leg. There are also some (Very rare) disorders that could also cause loss of blood supply and lead to necrosis.
However your silkie lost its toes, the treatment protocol is generally the same. I'll skip the "before" protocol since you are past that. Immediately after toes fall off, keep the live tissue at the terminal end clean, dry and medicated until the exposed live tissue scabs over and heals. Triple antibiotic ointment or veterycin spray is what most people use. I googled "Corona antibiotic" and all I got was info about covid19.
How long ago did the toes fall off? There shouldn't be any great concern for infection taking hold Unless the chick lives on soiled bedding. Keeping the bedding clean is paramount so that bacteria aren't introduced into the live tissue. Even though keeping the healing foot Unwrapped while it heals is preferred, wrapping Very loosely is ok if that's what it takes to keep the healing live tissue clean.
Auto-amputation is a mostly internal process that does an amazing job of sealing and separating live tissue from necrotic in order to prevent infection. With a little help from his human (you), your Silkie boy should be fine.