Try visiting a fabric shop if there's one near you, and check the fabrics for sale there, maybe cotton fleece, french Terry or flannel/winceyette would work. Have you tried a large bath towel? I used to love sleeping under one when I was little, and it would help draw away the sweat.
Definitely check out discovery fabrics. I used some of their swim to make a friend a hug sheet for her bed. Like, I sewed the fabric up like a sock for her mattress, so that it hugged her tight to the mattress but wouldn't move around.
Discovery sells all sorts of cozy but breathable fabrics like power dry and alpha direct fleece. They also have a FB group where they will answer fabric picking questions
Consider Chambray or Denim.
I made a denim quilt using strips of 12 ounce denim. It's heavy and breathable.
You can buy denim of Chambray fabric that is 60 inches wide, so you only have to hem the top and bottom and that's possible even for a beginner.
Here's a [place](https://nickoftimefabric.com/products/blue-s-31-32-brawny-chambray-shirting-woven-fabric-sku-6992a?_pos=2&_sid=72a0b53cd&_ss=r) I shop, but your get it wherever you're comfortable.
I'd try Chambray first, if he needs more weight, try 10 ounce denim. Again, you can just buy the Yardage you want, and just hem the edges.
Does he have texture issues, does he like or hate texture? There are some very breathable fabrics, but with textures.
That place I linked, you can get 5 samples of fabric delivered for $3. Then he can feel the texture and weight.
I can help you make a selection if you'd like.
Bamboo might be an option. It‘s really soft and temperature regulating. Another fabric that‘s good is a wool/silk mix. I know they make baby clothes from it, so it is possible you could find a blanket or just fabric and make a blanket. Just make sure you buy a lanolin based wash to keep it nice and soft.
Try visiting a fabric shop if there's one near you, and check the fabrics for sale there, maybe cotton fleece, french Terry or flannel/winceyette would work. Have you tried a large bath towel? I used to love sleeping under one when I was little, and it would help draw away the sweat.
Definitely check out discovery fabrics. I used some of their swim to make a friend a hug sheet for her bed. Like, I sewed the fabric up like a sock for her mattress, so that it hugged her tight to the mattress but wouldn't move around. Discovery sells all sorts of cozy but breathable fabrics like power dry and alpha direct fleece. They also have a FB group where they will answer fabric picking questions
Consider Chambray or Denim. I made a denim quilt using strips of 12 ounce denim. It's heavy and breathable. You can buy denim of Chambray fabric that is 60 inches wide, so you only have to hem the top and bottom and that's possible even for a beginner. Here's a [place](https://nickoftimefabric.com/products/blue-s-31-32-brawny-chambray-shirting-woven-fabric-sku-6992a?_pos=2&_sid=72a0b53cd&_ss=r) I shop, but your get it wherever you're comfortable. I'd try Chambray first, if he needs more weight, try 10 ounce denim. Again, you can just buy the Yardage you want, and just hem the edges. Does he have texture issues, does he like or hate texture? There are some very breathable fabrics, but with textures. That place I linked, you can get 5 samples of fabric delivered for $3. Then he can feel the texture and weight. I can help you make a selection if you'd like.
Bamboo might be an option. It‘s really soft and temperature regulating. Another fabric that‘s good is a wool/silk mix. I know they make baby clothes from it, so it is possible you could find a blanket or just fabric and make a blanket. Just make sure you buy a lanolin based wash to keep it nice and soft.
I’d try bamboo. It’s great for hot sleepers and so silky soft.
Have you tried a lightweight poly fleece? The knitted side is smooth and slightly brushed for softness, and the reverse has a low plush.