This may be a misunderstanding coming from not watching the program but…
My understanding is this:
Residence refers to home not place of business.
Khan would refer to the name of the occupant(s) (given its a residence, not a business)
They indicates more than two residents.
Given only a single name appears the deduction is that name relates to all or multiple residents.
So…
Multiple Khan makes Khans
The house belongs to (multiple) Khans so becomes Khans’
If it were the workplace of Mr Khan, a business called Khan(‘s) or only mr Khan living there it would be Khan’s Residence/office or what not.
Not that it matters any how, its all pedantry and internet posturing, it simply brings to mind something I was told as youngster by a teacher “if you’re going to be a dick about something, at least be right”. (I often forget ignore the second half)