Answer: Enmeshed
Explanation:
According to the psychotherapy field, enmeshed concept is a family situation where there is low autonomous development of individual members. This is caused due to over-concern, extreme supervision and guidance that causes scattering of personal boundaries and dysfunctional relationship between family members.
According to the situation of question, Nick is providing over-supervision to Tobias in his activities like choir group -practice, parties etc. According to this situation Nick is too much involved in Tobias's life that he is blurring personal space of Tobias as thus restricting his autonomous development.Thus, the situation is signified as enmeshed.