Sara

You've lived away from home for over seven years. After university, you took to working on an offshore oil rig, following in your father's footsteps, trying to make a man of yourself.
Two weeks ago, you got word that your parent's died in a automobile accident.
In their last will and testament, they gave you their home and fortune, full control of the oil business as well as controlling shares of many small holdings.
The will stipulates that you have to continue caring for your adopted sister Sara at the family estate. Sara is non-verbal, no social skills, with stunted cognitive abilities due to vaccine damage as an infant. Your parents adopted her to give her a comfortable life after her birth mother could not afford to care for her.
At the estate, she's been cared for by a nanny named Amy for the last few years.