Room is neutral so you can use any color towel you like.

If only your husband wants a rug to stand on, how about one small rug in front of his sink only?

I don't think a large rug will work very well because of the angled corner. It doesn't seem you'll be able to get the rug close enough to both sinks without running into the corner. I feel 2 small rugs would be the correct choice here.
I much prefer the look of the nickel and glass accessories. The brown is too matchy-matchy and uninteresting to me. Mixing polished and brushed isn't a problem at all, in my book.
You can use any color you'd like in this bathroom. If it's a master bath, maybe pull something in from the bedroom.

Maybe an oval rug would work with your sink configuration. Try searching for extra long oval bath rugs. You want non-slip in the bathroom.

This is a 10' from ruggable. You might be able to shape it for your needs since it's nice and long.

I would just put a smaller rug in front of his sink. Otherwise, a large circular rug may work with the angled cabinets. Your accessories don't have to match everything exactly. I would look for some with color, or colored glass for some interest.

You could get two patterned bath rugs - one for his vanity and one for the shower, for color and interest. Then take a color out of the rug for the towels.

Two machine-washable @18”x24” bathroom rugs (one in front of each sink, will keep bare feet warm if the floor isn’t heated. If you don’t want one for yourself, at least give Hubby a rug.

Two rugs in front of both sinks. I hate stepping on the floor without rug. Look at Serena and Lilly for inspo colors and towels, pottery barn has nice bathroom accessories, mix it up a bit, will look more organic

I don't think he's asking for too much. Let him have a washable bath mat.

Would three look silly?

Yes

One rug is fine if you don't want one for yourself but I would make sure its color is close to the color of your floor. I don't particularly like to accentuate a mat and even less if there is only one.

How can you not want a rug?

It should be fine to place one rug on the bathroom floor for your husband. See the image below from a design of ours:

Altadena Modern Farmhouse · More Info