An excellent question. Can it be done to be a best friend and the parent figure? And the answer is yes. Youths respect effort and energy on their behalf.
For the adult it is very very hard. But it can be done as my adult children tell me it is. It takes an amazing amount of effort and love. Some closeness and some distance. It requires mutual respect which is darned difficult for an adult. We are made into our roles. But we are first made into loving creatures that love others. If we as adults cannot see our purpose of building love and understanding in our youths then we miss out and God loses. We are bound by our existence to nourish other creatures including our youths. It is not easy and takes sacrifice but is well worth our immortal souls to be so good.
Our relationship must be cultivated. Punishment must be established by our own contrition. If one needs to somehow punish a youth then they have missed the boat. It has sailed. For it is within us to build character so that the youth punishes themselves. Not through guilt but by a firm desire to do better.
Some days I have not the energy to live in the moment with my young son. But by golly I force myself and push through the time. We must guide by being ever consistent and ever reliant upon our God. We establish our relationship with youth by example and sometimes that is hard. But living the right life is not always easy. But I tell you with certainty it is worth it.
Thank you for this question as it awakens me to my responsibilities. And it leads to a wonderful sermon that I need to write.