I would worry less about your sister who died young than about (for example) your great aunt who is still living at 101.
If there is a death date, the person will be visible. If there is no death date, but the person was born (for example) in 1912, s/he will be shown. My cousin Louise died this year at 103. No matter what I tried, she and her photos (many) and records were visible for the last 3 years.
The privacy rule is 100 years. Some/many people live longer than that, today.