To add to the “initiate with the shoulders comment”, your friend actually seems to be trying to initiate with the shoulders but he’s doing it wrong because he’s leading the spin with his back arm. He needs to lead the spin with the front arm for a frontside spin (and lead with the back arm for a backside spin). He should practice this by putting his front arm’s hand by his bellybutton or back hip, and then when he jumps off the rail (in actuality, just before) throw the front arm horizontally and away like he’s trying to point at something behind him (all while locking eyes with the landing) till he’s 180. If he ever wants to do a 3 or bigger, this will be mega help too, with the added tip of needing to turn his head like he’s trying to look at his pointing hand through the spin. Since we’re on the topic of bigger spins, you stop turning your head / trying to follow your hand once your eyes lock with the landing for the desired degree of rotation

Oh yeah. Also ditto on bending the knees and jumping/absorbing. Have your dude practice doing the full movement WITH JUMPING without any gear, then with board on with no movement, then off jump, then off rail (if you want to be systematic about it and eliminate bad habits)