Complex sentence: 'Jack becomes good friends with Capeside's instigator, Jen Lindley, whom he convinces to move in with him after Grams kicks Jen out and he decides to remain in Capeside while his sister Andie seeks medical attention at a psychiatric hospital.
Split into simpler sentences: 'Jack becomes good friends with Capeside's instigator, Jen Lindley. After Grams kicks Jen out and he decides to remain in Capeside, he convinces Jen to move in with him while his sister Andie seeks medical attention at a psychiatric hospital.