Despite their roles as adult counselors, neither Friar Lawrence nor the Nurse offer good counsel to the young people who seek their advice. Friar Lawrence does not serve Romeo well as a counselor when he agrees to marry the young couple. He is clearly thinking more about settling the feud than what is prudent for a young, lovestruck, and impetuous Romeo. He does not serve Juliet well as a counselor when he abets her in a plan to thwart her parents' authority, a plan that does not seem particularly consistent with his hope to end the feud. The plan is also physically risky, first regarding Juliet's life and second regarding a message getting to Romeo in a timely manner. The entire plan is fraught with possible problems.
The Nurse gives Juliet terrible counsel. First she assists her young charge in deceiving her parents without any real thought or deliberation or even discussion. Juliet wants Romeo so she helps Juliet get him. This romanticized behavior is understandable in Juliet but not in her adult counselor. Once Romeo has been banished, the Nurse gives Juliet equally bad advice--forget the marriage vows she made to Romeo because he is gone and make new ones with Paris because he is a fine man. She is just not reasonable and her counsel is neither mature nor consistent.