What are the key ‘privacy features’ that Internet of Things Systems should provide to facilitate ageing independent living?

What literature says?
What are the key ‘privacy features’ that Internet of Things Systems should provide to facilitate ageing independent living?
How do current support systems support those needs?
What are the key differences between vulnerable and non-vulnerable groups regarding privacy needs, and how should such needs be facilitated?
Can voice assistants help older people to control the privacy of smart devices?
How efficient is that? and compare (GUI vs VUI)