Complex sentence: Cameron helps his mother as primarily caregiver of his Grandma, Grandpa and niece after his sister is kicked out as her drug addiction lost Angie's (Cameron's niece) twin brother, Jamie.
Split into simpler sentences: Cameron helps his mother with the care of his Grandma, Grandpa and niece after his sister is kicked out of the house. Her drug addiction was a contributing factor in the death of Angie's (Cameron's niece) twin brother, Jamie.