Ttdfjt

I have this duo in my novel, they're always together in chapters. Usually the story alternates between them within their plot, though mostly leaning to one of the characters, as he's one of the MCs and he's pretty significant to the plot and world.

Though, since they're so much together, they get a lot of attention also in the chapters they're not the POV in. That's okay obviously, but in the latest chapter, the attention almost completely shifts to one of them, who isn't the actual POV of that chapter.

The reason for this is that the other character gets drunk. They're on this mission, and the POV character has a more passive role in it. That narrative asks for more attention to the doer, but that's not in-line with who is the POV, and the center of attention for the beginning parts of the chapter.

So, is it okay to shift the POV as the chapter progresses? The chapter will end with the POV being the center of attention again, there's really only a little segment where the other character kind of takes over.

EDIT: When I meant who is active, I mean we see things from their perspective, because they are the one who is doing something. We see their preperations, even though the actual POV is not in the same room. And their emotions are described, not directly, but through surface level cues. So I would say it pretty safe to say the actual POV shifts, and it isn't a Holmes and Watson case. But as Galastel said in his answer, it is okay to shift POV, and it is really more of a question how.

There are two questions hiding in your question,

1. Can the POV character not be the character who's most active?

Consider Sherlock Holmes as an example. Watson is the POV character, the story is told in first person by Watson, it's Watson's opinions and emotions we share. But Watson is passive. It's Holmes who is active, it's Holmes who is interesting, it's Holmes who is the focus of the story.

There is nothing wrong with writing part of your narrative in a similar fashion, with the POV character observing, while another character is more active. If that's what suits your narrative, that's certainly a tool you can use.

2. Can you switch POV mid-chapter?

In her novel The Merlin Conspiracy, Diana Wynne Jones follows two POV characters who start out in two very different locations. Each "part" of the novel is labelled with the appropriate character. Then, as the characters meet, the labels are attached instead to each chapter, (and those can be one page long,) and then they just hover over paragraphs mid-chapter, when the switch happens. It's not disruptive in the slightest, but if you think about it, there's buildup for this happening, structurally.

As an alternative, you can write in 3rd person omniscient, in which case you are in whatever head you need to be in all the time. This question goes deeper into it.

So, to sum up, this isn't a question about whether it is OK - it is, but about how to do it. There are multiple ways, you need to pick the one that works best for your particular narrative.

Break the chapter into three scenes. Each scene has a POV character. First and last scenes have one POV character. Middle scene has the other POV character. Since the scenes in the chapter will differ only in time, make it clear on the scene transitions that the POV has changed. For example, scene two starts with the clearly identified POV character of the second scene thinking that the POV character of the first scene is a fool for drinking so much.

There are no hard and fast rules about POV. There are different techniques that you can choose in order to produce the effect you want. Some of the techniques are harder to carry out than others.

What generally goes wrong with unskillful handling of POV shifts is that shift is either jarring or confusing to the reader, which breaks the "reader's trance" and pulls them out of the story. One way of dealing with this is to have scene breaks and clearly marked transitions in the text. Then although the POV shift is sudden, it doesn't feel wrong to the reader, because they know it's happening.

Another technique is to write in transitions that gently helicopter us out of one POV and into another:

That little brat Will was chewing gum. Sister Wendy locked her gaze on the boy, who continued his chewing while staring out the open window by his seat in the corner.

The children's heads turned, and there were a few smiles to be seen. A warm breeze blew in through the suddenly silent room, bringing the smell of the stables on the other side of Main Street. A little brown mare was hitched out front, where she'd been led, limping, on a halter. Something was wrong with her left front foot.

Will dug the tip of his fountain pen into the palm of his left hand and bit down on his lip. Was it a split hoof? That would hurt a lot for sure. Or maybe someone put a shoe on and did it wrong.

A nice example of a POV shifting back and forth between two main characters, with no clear demarcations, is the Patrick O'Brian Aubrey-Maturin novels.

To me it generally feels a little awkward when you have a whole novel written predominantly in one POV, but then one part of one chapter shifts the POV. It feels asymmetrical and violates the expectations that have been set up in the reader. If it's really necessary to do this, I would try to avoid creating that expectation, by varying the POV in more subtle ways elsewhere in the book.

The traditional way of doing things would be to have one POV per chapter, or, if you must switch within a chapter, to divide them with a section break.

But, as a general rule, less "head hopping" makes for stronger writing. Multiple POV changes are hugely popular with newer writers, but you don't see it so often in successful published works. It's a very difficult technique to write well. Putting the reader into the headspace of a character takes some effort, and continual changes of perspective often create an emotional distance between reader and characters.

I think it is fine to shift, but I think you need a marker of some sort to ensure the reader is aware of whose POV they are in.

This could be done in prose, but it might be easier to just use the scene separator within the chapter, usually three dashes centered on a line, to signal to the reader something is changing. Normally this is a time skip within the same setting, or a change of setting but it can be used to signal any kind of change, including a POV change.

I wouldn't mix multiple POVs in a sentence by sentence or paragraph by paragraph fashion, just use the "---" and begin the next sentence with the name of whichever character is now the POV. When we switch from Susan to John, for example:

                                             ---

John walked to the kitchen, looking for a sponge to clean Susan up [...]