"I told him not to buy a white ski suit because it's not very visible in snow, but he ignored me and bought it anyway"
I don't know what you mean by "white ski wear", do you mean "white ski jacket"? "White ski suit"? "...because it's not very visible in snow" you can keep the phrasing you had but it's not necessary and sounds a little awkward.
I advised him to buy ski wear of any color other than white, so that he would stand out against the backdrop of the snow, for safety reasons. He didn't take my advice. He didn't seem to care. He ignored my advice. I told him not to buy white-colored ski wear.