Final answer:
Yes, there can be a social tie between you and your best friend's uncle even if you have never met him.
Step-by-step explanation:
The statement, 'There is a social tie between me and my best friend's uncle even though I've never met him' is true. According to the information provided, the concept of sacred relations is discussed, highlighting that distant cousins are considered as sacred as a brother. This suggests that even though you've never met your best friend's uncle, you still share a social tie through your friendship bond.