This is B# (be sharp) eating and drinking.
I am neither an expert nor a vet, but merely share hands on experience.
ONLY use a glass eye dropper, as seen in the video. Some chemists stock them, cost about $5.
A very young fledgling only needs a honey water mixed to drink from the glass eye dropper. Do NOT insert the eye dropper into the mouth. The bird will lap the end o the eye dropper with its long nectar eating tongue.
When the fledgling is a few days older, as B# is in the video, feeding small balls of food is good.
Comments, questions and suggestions welcomed.