Final answer:
Neville's relatives feared he was a Squib, but this was disproven when he showed latent magical abilities after a fall. His development reflects the journey from realistic aspirations to discovering one's true potential.
Step-by-step explanation:
Neville Longbottom's relatives feared he was a Squib, which is a person born to magical parents but with no magical powers of their own.
This concern was disproven when he was accidentally dropped out of a window and bounced safely, which demonstrated he did have magical abilities, albeit latent ones.
While growing up, children might have more realistic career aspirations, such as becoming an engineer instead of a wizard, but it is the unfolding of Neville's magical potential that shifts the perception of his family towards him.
The journey from fear of being non-magical to the discovery of Neville's true abilities serves as a minor subplot in the larger narrative of the Harry Potter series.