Boyfriend's parents don't agree to send text messages in private.

In fact, people's hearts are fleshy. Boyfriend's parents disagree. Don't send private messages. That is to influence him with your practical actions. Be kind to them. Show your sincerity. Treat your boyfriend and his parents. Of course. Face to face with him. Tell him how much you love his son. You will make his son happy all his life. Do it with practical actions. It's been a long time. I'll accept you slowly.