Peeing on these soft surfaces might mean he's in pain - when a cat has a UTI/bladder infection/kidney infection they usually find somewhere soft to stand (clothes/rug/bed/) when they go, in the hopes it won't hurt the same way it did when they tried in the litterbox.
When he had his last full bloodwork test did they check the T4? HyperThyroidism is normally an older cat condition but
it's possible
Did they check his kidney functions?