Complex sentence: Regardless, Greg decides to take him under his wing, however Greg more frequently proves to negatively influence his friend than to set a positive example for him, earning himself the distrust of Rowley's parents.
Split into simpler sentences: Regardless, Greg decides to take him under his wing. However, Greg more frequently proves to negatively influence his friend than to set a positive example for him, which earns himself the distrust of Rowley's parents.