Wanting to know more about a young rook that died!

I recently found a young Rook in my grandparent garden and when I arrived they said it had been there 2 days - they had been throwing bread out but had otherwise left it alone. There was a large nest in the big trees above with lots of other Rooks flying about and nests visible high up in the trees and lots of noise! The young chick was full feathered and looked sprightly but was only able to get a few inches off the ground when it flapped its wings but didn’t look injured or in any distress, apart from clearly crying to its family above for food. The weather had been warm so I left a bird bath out and some berries, and it was happily drinking and dunking its head and cleaning itself in the water. However when I returned later that day it had died in the shrubs. It hadn’t been attacked as garden is fully enclosed. I didn’t see its parents come once to feed it and it had been walking around for days cawing up at them. I felt sad for it as I’d read they were social and usually would come and feed the chicks if they got stuck in gardens but this didn’t happen. I’m wondering if there is anything else I could have or should do next time if this happens and also if anyone had any idea why they would have just left the poor thing alone for days knowing it was there?! Thanks :)