Best friends

Nowadays Benji is really interested about the meaning of "friends" and "friendship". His little cars come in pairs, he tells me that the little green car's friend is the red Ferrari, the soft toys come in pairs too, and I know that in nursery his friends are Harry and Olivia, but Declan is not.
We were looking at our wedding photo the other day and he had to name everyone he knew on it, then he pointed at Doug and asked who he is. I said he is Daddy's best friend.
Then for about 1-2 minutes we forgot about it, went on our ways, then all of a sudden he turns to me:
- Mummy?
- Yes?
- My best friend is Dina.

He said it in such a cute, serious way that I really wanted to lift him up and kiss his clever face to pieces.
(It is a shame that the named person couldn't see it...)