So the second story balcony is collapsing and I was wondering how to go about fixing it? There's also a light fixture in the middle of it.

It may take more information to help you. What is it made of? Cement, wood, something else? Is there support under it or is it suspended from the home.

Posta picture and also tell us where you live. There are too many types of balconey's to answer this blind.

Where you live is important. THere are strict codes that apply and require inspections in many if not most places in the USA. This may or may not require someone familiar with local codes to replace/repair.