Pig lung transplanted into a human

I’d love a hard sci-fi story where they implant chunks of pig brain into brain damaged humans, trying to maintain as much “life context” but bringing in new brain matter to help them function again.

I think our neurons are actually different in significant ways, might be more accurate and interesting for them to use brain organoids.

Star Trek went into this a bit. There was an episode in which the technology behind the android Data's artificial brain had been turned into a medical treatment used to prolong the life of a recurring character who got injured, and the ethical question of the subplot was roughly "how much of their brain can you subsitute with functional but essentially generic hardware before they cease to be themselves, making the rescue attempt fruitless".

Most people will probably not remember this - it was the death of Kira's lover Bareil on DS9 - because it was almost throwaway, but it was one of those sparkling little ideas and questions Star Trek used to be filled with that has stayed with me life-long.

Not exactly what you asked for, but Alastair Reynolds have books with "hyperpigs" that are part-pig, part-human, likely bred to be replacement parts for humans.

I've been reading his novels, and I like the story of the pigs.

Genetically tweaked to be more compatible with the humans that might harvest their organs, but then they became a bit too human. Then scientists were like fuck it how far can we go with this. Hyperpigs.

Scorpio is not as interesting a character as I would like, but he's a good pig.

A great take on the Ship of Theseus.