Most of the fabrics we sell are made of 100% cotton, ( we also have some kente fabrics that are a mix between polyester and cotton ). This information can always be found in the product description of that fabric.
The cotton fabrics have a cotton weight / thickness of between 120 grams per m2 and 190 grams per m2. ( this is different for each brand )
We have many customers who upholster chairs and sofas with it, so it is certainly possible. (You can find pictures of this regularly at our customer reviews and on Instagram)
We just don't have any technical information available on abrasion resistance, as it has not been extensively tested as a furniture fabric. They are not fabrics specifically developed as furniture fabrics, but they can certainly take some, as they are high-quality cotton.
So the question is also a bit of how often it will be sat on, and whether sharp things often come into contact with it, for example if it is a waiting room chair or car seat. If you want more firmness, you can possibly use an extra layer of, say, an even-colored upholstery fabric as a carpet pad.