The phrase "as a friend even" is correct and usable in written English.
It can be used to emphasize a point or express a sentiment that is surprising or unexpected, particularly in the context of friendship.
Example: "I can't believe you would betray me as a friend even after everything we've been through."
Alternatives: "even as a friend" or "as a friend, no less".
I would walk around and go into someone's office and talk to that person as a friend – even if I didn't know their name.
I'm really pleased that you would think to consider me -- a 30-something balding P.R. guy -- as a friend, even if only on Facebook.
And when Boris re-enters Theo's life in adulthood it is impossible not to hope he is there as a friend, even while fearing the opposite.
These aren't private conversations we are eavesdropping on: Kennedy was speaking to Schlesinger as a historian, rather than as a friend, even if she clearly trusted him to be friendly when it came to her image and her husband's legacy.
He once corrected someone who had called a painting of his "only a picture of a house", by pointing out that it was a picture "of a summer's morning, including a house".He liked to think of the landscape as a friend, even as his mistress.
You are your only way to stand with a friend as a friend, even when she perceives you as an enemy.
Don't think about the camera as being a friend, even though you may or may not know when or how you bought this camera.
We are all used to gathering quick information about a friend of a friend, even getting as specific as family vacations and birthday celebrations.
But after his death, newspapers in Scotland reported that Mr. Miralles had told a friend, even as he was dying, that he was disillusioned that the project had become so politicized.
I count her as a close friend even though I met her in person only minutes before her November 7th workshop at Columbia.
He too eagerly stressed his significance as a friend (and even got himself buried next to Keats, as though he was something like a wife).
