Facts
[X.] and [Y.] are the unmarried parents of the twins [A.] and [B.] , born in 2000, and of [C.] , born in 2001. In the summer of 2008, the parties separated. After the parents had alternately cared for the children, the President of the Social Welfare Authority [D.] on 15 October 2008, based on a report of danger from the father, revoked the mother's parental custody over the children, ordered their external care and established a guardianship. By decision of 15 September 2009, the Social Welfare Authority placed the three children back under the custody of the mother, while maintaining the guardianship. Subsequently, there were several decisions and appeals regarding the father's right of access. Finally, the High Court of the Canton of Zurich, by judgment of 26 August 2013, denied [X.] a right of access. Against this decision, [X.] filed an appeal, which the Federal Supreme Court upheld on 17 October 2014 and remanded the case back to the High Court for re-assessment.Considerations
The High Court subsequently heard the three sons again and appointed them a representative. In its judgment of 29 May 2015, it assumed a changed factual situation and therefore again denied the father the right of access. The High Court considered that the twins [A.] and [B.] were now 15 years old and [C.] 14 years old. In the hearing, they had not categorically rejected visits with the father, but it was true that their statements had been made under the premise that visits should be ordered according to the Federal Supreme Court's guidelines. The fact that they did not want visits on their own initiative was shown by the circumstance that they had not had any contact with the father in recent years and…