Son asked me a hard question about why bad things happen

My 10yo asked me why his friend's dad got cancer and if God was punishing him. I had to sit with that one for a second. Told him that bad things happen because we live in a broken world but God is with us in the pain. We prayed for his friend's family together. Later my wife said he was asking about suffering and faith on his own. Makes me realize I need to be more intentional about teaching them deeper faith stuff, not just surface level stuff. Praying for wisdom on this.