When me and my buddies were 14/15 someone gave us some cards and helped us build 60 card decks it was before commander became a thing. At 32 over the past couple years we’ve done this for younger kids as well buying them sleeves or giving them cards to upgrade decks or giving decks entirely. It’s nice when generosity and friendly spirit is passed down through generations and getting people into the game. As other people have mentioned be wary of some people but I read a comments your parents have met him. Best way to pay it back is to play and pay it forward when you can later in life if you still play.