Hoenstly, I don't like it either. I'd either remove it or cover it up.

I like the color of the stones, they’re nicely neutral.

I’ve never seen holes like that — I guess it’s venting of some type? If so, it’ll of course need to be take into account regarding updates.

Changing the brass out would be a big difference:

A mantle (above vent) would help distract from the ”teeth” (lol).

It’s hard to say, though, without knowing his decor preferences and what will be in there. Does he like sleek and modern, for instance? MCM? Etc.

LOVE the stones and the cement base. Agree that the teeth are strange and one black stone sticks out. perhaps the black stone can be lime washed to tone it down? not sure about the “teeth”. Are they functional? And doing a matte black for the actual fireplace would look really nice. or a nicer actual brass would look good too.

The stone is nice, the insert is not. The "teeth" hot air ducts for a "Heatilator" fireplace. So the gas insert bypasses those and they no longer server a purpose. Certainly that large fake brass front needs to go. Do you plan on keeping the insert or possibly pulling it out and burning real wood or going with a nicer looking gas log or glass fire?

A lot can be done to just make the opening look good, but we need to know if you have any plans for it's use.

Pretty wacky. Paint it black so the teeth recede.

Ha ha ha ha, sorry but it makes me chuckle. I understand your son's dislike tho. : )

I would remove the brass, or paint it black. Then put a thick rustic mantle over the scary teeth, and white wash that black rock.

Can you replace the teeth with some stone that blends well. A good stone mason will be able to make it look like they were never there.

Thanks all! I totally agree, the brass will be painted black for sure. I like all the ideas!! Lime washing that one stone I’ll try and definitely the mantle. We’ll see if that’s enough of a change for him. Thanks everyone!

Oh anyone know if you can change the color of stone by washing it with something?

Here’s a good article about stone enhancers.

https://www.hunker.com/13416082/what-can-you-put-on-natural-stone-to-bring-out-its-natural-luster

I agree with the suggestions except it's important to know, I assume the "teeth" are a vent so can't just be covered up.