bump

Is that a movable FP and can it be brought out of the corner to a flat wall? Ditch the clock unless you don't own any digital devices to tell you the time. Rug on rug can be tricky. It needs to ground the sofas so it will cover most of your carpet. With the corner FP (if it can't be moved) you have a shape problem with the rug too. You might try "C" tables with the sectional and a coffee table with the sofa. First get the FP/TV issue arranged. Can they be moved? Can you get rid of that ridiculously over-sized mantel?

Don’t mount the tv, there’s nothing wrong with it on a console like you have it. Try pushing it back so the wires aren’t so noticeable. Clear the mantel, remove that clock, get pattern and color in there with throw pillows. Don’t skimp on the throw pillows, get nice ones. What are some accent colors in the rest of your house? Wall art and plants!

You didn't comment on the mantel, but it does seem really large. I wonder if painting it the same as the wall color would help minimize it?

1. Is this a rental or do you own?
2. Is the wall to wall taupe like it appears in one picture or gray like it appears in a different picture?
3. Why does the sectional and sofa not match?
4. Do you have a TV hook up above the fireplace?

Clock might be moved to entry and still be visible from living room? Or put it with a modern corner zig zag wall shelf displaying a family treasure or two that would brighten the room without crowding the right corner (first pic).

Wouldn't add a rug over carpet. You could add more color via a few throw pillows. Don't add so many they become clutter.

Adding black painted feet or (lockable) wheels to the tv console would raise it a bit without investing in a new console or hanging it on the wall if you decide you want the tv higher.

Might consider a square or round storage ottoman for the "L" shaped sofa -- perhaps with a lid that flips so it could be used as a coffee table. If you choose a coffee table instead of an ottoman, don't pick a square cornered knee knocker -- go with round or oval.

If you're handy with wood and have a saw and hammer, you might be able to make your own Zig Zag shelves:

https://www.homedepot.com/pep/DANYA-B-Zig-Zag-7-75-in-W-x-7-75-in-D-Floating-Laminate-Corner-Wall-Decorative-Shelf-in-Weathered-Oak-Finish-XF11035OK/301308128?cm_mmc=Shopping%7CG%7CBase%7CD59%7CMulti%7CNA%7CPLA%7CAll_Storage%7c71700000032301830%7c58700003837074630%7c92700045164361147&gclid=EAIaIQobChMIsr75ya2V5AIVTQOGCh0iFQqlEAQYBCABEgJ78PD_BwE&gclsrc=aw.ds

I assume your brother owns the home and you are helping him with decor.

The TV is on the correct wall. I'd replace that wimpy TV stand with one that is as long as he can get it. Get rid of the clock. Lean a large piece of art on the mantel.

I would replace the carpet with a hardwood floor. If keeping the carpet, skip the rug. Use whatever art he chooses for the mantel to inform the accessories in the room.

If you really want to help him, sit with him and go through photos of living rooms on Houzz and have him save his favorites to an ideabook. You might filter them by looking at rooms with gray couches so he doesn't end up with rooms he can't achieve.

It is a really a nice setup...!