Complex sentence: Wilson and his mother dismembered Bill's body and dumped pieces of it into the river every night, followed by Fisk going to live with some relatives for a while with Fisk keeping his father's cuff links as a reminder to never to be like his father.
Split into simpler sentences: Wilson and his mother dismembered Bill's body and dumped his remains into the river. Fisk was sent live with relatives for some time, and in the present day, keeps his father's cuff links as a reminder to never to be like his father.