Depends how big his waist is,my 11yr old can't because he's super skinny but they were my 15yr olds at 12 & he was bit huskier. If you can measure his waist just from side to side across front :)
Sorry hun,Got wrong auction! Thought you were commenting on other pair i have up,those would fit your 12yr old. These will fit a 5 or small 6 yr old :)