You can't make someone grow up. For example, my brother in law. He refuses offers of advancement at work because he's satisfied with the position normally held by teens. He frequently makes the rent checks bounce because he's ordered a part for his hobby off the Internet. I could go on and on. By the way, he is fifty nine years old.
The person can only do it themselves. You cannot change a person or make them change or grow up. I often ask myself this question hoping that a certain someone will grow up, but it's hopeless. In time depending on age a person may mature, but in some cases some never do.