I wrote about this* over 3 years ago and I was reminded about it again last Christmas... while watching Mammoth Christmas.
I smiled when Manny's daughter, Peaches refer to Sid - her parents' friend - as "Uncle Sid." These days that more and more people call people older than them by their first name it can be an uphill task to help children refer to their elders respectfully. There are many ways to teach a child how to do that. One way I've found to be effective is when they are still imitating and repeating everything - or almost everything you say, I refer to other adults as "Uncle" or "Auntie" so and so.
It has worked rather well with my children such that the only name they know for that person is "Uncle this" or "Auntie that." It's almost funny - but great - to hear them correct themselves when they unthinkingly refer to the person as "Brother" or "Sister" as I would.
When the school year started, it was nice almost startling to see the switch when one of my children's teacher was introducing himself to his students. He was clear on what they should call him - "Mr. so and so." Without missing a heartbeat when he turned to introduce himself to me, he said my name is "So and so" - yes his first name. So the distinction was clear and reinforced my resolve to help children in my sphere of influence understand that.
I know it's not easy for some children to understand why they should call someone that isn't on their family tree "Uncle" or "Auntie" however, it is important for them to understand that it's about the bond not just blood.
I know about this from personal experience. I have an Auntie who has been and continues to be a superb blessing to me and my family. In fact my children, know her as "Grandma." Auntie T, I love and appreciate you more than words can ever say. May God continually bless you and yours.