I wonder if they would like a quilow - both my darling daughters loved them because they could put their feet in the part where the quilt folds into and when it is open. And when finished it folds into a pillow on their bed. My daughter works at a facility that is a boring school for kids removed from bad homes and no foster family available. Those kids come with very little. most do not even own a suitcase. They bring their belongings in a the plastic trash bags.
You can use a local team fabric, sports fabrics, really any type of masculine fabric. A lot of young men of that age also love the Marvel and DC movies and like that type of bedding. Also Star Wars and Lord of the Rings are good. If you go into a shop that sells a lot of t-shirts to kids you can get an idea there too.