Complex sentence: Riis was influenced by his father, whose school Riis delighted in disrupting, and who persuaded him to read (and improve his English via) Charles Dickens's magazine "All the Year Round" and the novels of James Fenimore Cooper.
Split into simpler sentences: Riis was influenced by his father, whose school Riis delighted in disrupting. His father persuaded him to read (and improve his English via) Charles Dickens's magazine "All the Year Round" and the novels of James Fenimore Cooper.