Order unanimously affirmed without costs. Memorandum: We reject the contention of petitioner that the determination denying her petition for sole custody of the parties' son and granting custody to respondent lacks a sound and substantial basis in the record ( see, White v. White, 209 A.D.2d 949, lv dismissed 85 N.Y.2d 924; Fox v. Fox, 177 A.D.2d 209, 211-212) and is against the weight of the evidence ( see, Matter of Paul C. v. Tracy C., 209 A.D.2d 955, 956). Respondent met his heavy burden of proving that the change of custody is in the child's best interests ( see, Matter of Ammann v. Ammann, 209 A.D.2d 1032; see also, Eschbach v. Eschbach, 56 N.Y.2d 167, 171-174; Friederwitzer v. Friederwitzer, 55 N.Y.2d 89, 93-95).