Complex sentence: Blake begins beating himself up emotionally and his mood swings worry Alf, Ailsa and Grant and he confesses that he blames himself for his mother's death of cancer and feels the stress of his time in juvenile detention for car theft caused the cancer.
Split into simpler sentences: Blake begins beating himself up emotionally and his mood swings worry Alf, Ailsa and Grant. He confesses that he blames himself for his mother's death from cancer and feels the stress of his time in juvenile detention for car theft caused the cancer.