Don’t ever second guess your gut reaction. The boy was wrong in swearing at his father, but what his father’s reaction was, was inexcusable. God was speaking through you at that moment. You did the right thing. The wrong thing would have been to have done nothing. It probably wouldn’t hurt to invite them over for a barbecue at a some point. It sounds as though they are both under an incredible amount of stress. I’m sure this isn’t the first time the man has taken his aggravation out on his child in this manner. You can reach out by being a source of caring for both of them when you feel it would be a good time, and the man doesn’t think you’re doing this to be a busy body. It sounds like they both need someone to watch over and to show them some kindness, and maybe a little charity, right now.