Mens athletic pants, black, size medium

In very good condition mens joggers. They are black with a red and white stripes down the sides, elastic waist. There is no sizing tag. This is 1 of 3 different pairs of joggers I am listing that belonged to my son who has Autism. He hates tags in his clothes so I have always had to cut them out. I am calling these a medium but please use my measurements below to make your decision. Waist measures 16 inches across when laying flat Rise measures 12 inches Inseam measures 30 inches