Complex sentence: In Season 1, Burt suffers from mental illness due to the stress of accidentally killing Mary's first husband, and the murder death of his son Peter, and believes he can make himself invisible by snapping his fingers.
Split into simpler sentences: In Season 1, Burt suffers from mental illness due to his guilt over accidentally killing Mary's first husband, and the murder of his son Peter. For a time, he believes he can make himself invisible by snapping his fingers.