My brother sided his new home with 16 in. red cedar shingles , 5 in. reveal, with no stain or sealer. Today,a year later they are getting kind of fuzzy almost rough. It seems worse in the sunny areas which isn’t much as his house is in the woods. He was told to scrape them down and put a preservitive on them or stain. What would happen if he didn’t do anything? I thought they would just darken to the black or dark brown as you see in New England.
What do you guys think he should do?

Thanks

Roy