HanesBoy's Hanes Ultimate Boys' 5-Pack Boxer Briefs Boxer Briefs

It’s is the fabric woven or knitted cotton?

I bought small in men’s and it was too big so I want to try a size in boy’s. What’s the waist size for small and medium?

Are these sizes consistent with other Hanes boys underwear?

What size should I choose for a 12 years old boy? He usually wears size 16