I have no clue, it depends on what his sensitivities are. Somebody suggested hoodies and they wear them a lot now. Mine are 26, 21, 20 and 18 but hoodies have been popular for years and still are. I have tons of them around here for the two kids who still live at home. They do have weight on them.
If it's wanting something tight or squeezy feeling that he wants, what about emo jeans? Skinny jeans are really tight and are pretty popular although they look horribly uncomfortable. I have one pair and don't much like them. I don't wear Mom Jeans but I also don't wear skinny jeans like the emo's do. But they are tight, easy to find, and popular.
Also, what about those woven hemp style hoodie or poncho shirts he could wear over a tshirt? They are soft and also heavy. You could probably find them wherever you find hippie or New Age type clothes. Wherever the Burning Man people go lol. And Phish fans. And anywhere in Seattle too probably.
Another soft thing is flannel. You can get flannel button up shirts without tags and they are soft as can be, especially after washing.
There are always sweat pants. Those are popular. I've also seen lots of kids wearing night pants around in town and to school. Seems to be a growing fad. Maybe it's something that could help.
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I'm giving it another shot. We will see.
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The link to the forum is
http://www.rightplanet.proboards.com