This character is a mentor.
A mentor is a trusted friend, counselor or teacher, usually a more experienced person.
Some professions have "mentoring programs" in which newcomers are paired with more experienced people, who advise them and serve as examples as they advance. Schools sometimes offer mentoring programs to new students, or students having difficulties.
Today mentors provide expertise to less experienced individuals to help them advance their careers, enhance their education, and build their networks.