Boromir and Hobbits is a collection of scenes of him being baffled by the Hobbits. And mistaking Pippin for a child. And being surprised at their friendliness. And also it's based on that one massively long post about Hobbits having a wildly different way of reckoning kinship. Oh also I have tried to render that line in the Appendices about the Hobbits always speaking in the informal by having them use the thou/ye distinction of certain dialects like Yorkshire English mixed with Hiberno-English conventions around plural "ye." Here have a snippet!
The Fellowship ate in grief-laden silence for a while. "Well, it seems we are all blood-brothers after this," said Boromir as though it were the only scrap of comfort in the whole horrible situation. There was a murmur of agreement and nods from Legolas, Gimli, and Aragorn; though not from the Hobbits.
"Come again?" asked Merry, certain he had misheard.
"I said that we are blood-brothers after this ordeal, if we were not before this day," the Man said, a little louder. The Hobbits exchanged baffled looks.
"Art thou alright?" Merry asked him, being the only Hobbit who wanted to speak.
"I am as alright as any of us are, why ask?"
"Well, what thou saidst didn't make much sense. None of us here are blood-brothers, unless maybe thyself and Strider are."
"We are," was all Aragorn said, sending Merry a searching look.
Boromir looked at the Hobbit then, made a dismayed sound, and returned to staring into the fire. "Then I wish it were that we would be blood-brothers."
Again baffled looks were exchanged among the Hobbits. "Thou wishest I were a Man? Or thyself a Hobbit? Or one, or both of us half-Man half-Hobbit?" asked Merry, bewildered.
"This is no time to blaggard. I, for one, am in no mood for even listening to it Mr. Meriadoc, Mr. Boromir," said Sam sternly.
"What has Race got to do with blood-brotherhood?" Gimli asked, ignoring Sam.
"What hasn't it got to do with it? We couldn't be blood-brothers unless we had a blood-mother or father in common," Merry said as though stating the obvious. "Though I'm sure thou'dst make a very fine brother," he added, patting the Man on the knee who gave him a befuddled look. Legolas and Gimli were looking at him just as strangely.
Aragorn however looked thoughtful as he said: "Gentlemen, I believe I understand the source of our confusion. I think that Hobbits must use the term 'blood-brothers' to mean brothers related by blood: which none of us here are. What Boromir meant was that we are brothers-in-arms, so to speak."
"Ah," said Merry understanding, "we Hobbits call that pledged-brotherhood. Sorry for not understanding, Boromir, I'd be thy pledged-brother gladly. And would be all yers if ye'd have me."
The other Hobbits nodded in agreement. " 'Course we would," said Sam. "I'd have been yer pledged-brother since before...all that in the dark."
"Hear! Hear!" Frodo and Pippin agreed quietly.
"Don't Men make a difference between pledged and blood kin?" Merry asked suddenly.
"We do," said Aragorn, "though clearly we use different words to Hobbits to describe it. Come!" he said getting to his feet. "We must not linger!"
They put out the fire, hid its traces, and made off.