I taught my brother how to do it. Do you have any siblings? Because my technique requires them.
My parents did not trust my younger brother to follow through or be responsible. What i did was slyly interview them and try to get to the root of their issues and exactly what they thought he had to improve on (you’d be suprised how happy your parents are to discuss their issues with you with your siblings). I also asked what they would like to see him do. With this information I came back to my brother and we made a long term (several month) plan of goals and attitude adjustments to be made along the way. It took some work but he matured enormously and accomplished everything he wanted to and my parents are over the moon happy, proud, and trusting :).
This process can be frustrating, because IT WILL be a constant critique of who you are and why you are the way you are. Most importantly do your best not to blame others or lash out.