Complex sentence: He used to live in Smithfield, Dublin and while there knew a homeless guy who used to be a boxer; they called him Rocky, he got drunk and smashed their window he used to sleep outside in the laneway.
Split into simpler sentences: He used to live in Smithfield, Dublin and while there knew a homeless guy who used to be a boxer; they called him Rocky. He got drunk and smashed their windows and used to sleep outside in the laneway.