Complex sentence: Mr. Verloc is also a businessman, owning a shop which sells bric-a-brac, where he lives with his wife Winnie, his mother-in-law, and his brother-in-law, Stevie.
Split into simpler sentences: Mr. Verloc is also a businessman who owns a shop which sells bric-a-brac. Verloc lives with his wife Winnie, his mother-in-law, and his brother-in-law, Stevie.