Aw, Brinjal, how wonderful! But baby birds do need to be fed almost constantly during daylight hours. Chopping up mealworms or feeding earthworms would be fine. There's no way that the parent birds will be back now, as baby has been tainted by humans.
Baby will let you know when s/he's had enough to eat, but you will wear yourself out! Hopefully someone can help you. I raised an orphaned blackbird once, and it really was a full-time job.
Looking forward to seeing some pics soon!