Child custody dispute between parent and nonparent; Non-biological grandmother, intervenor, who helped raise child had standing to intervene in child custody proceedings but was not entitled to custody or visitation where intervenor failed to demonstrate that mother was unfit or acted inconsistently with her protected parental status; Mother's decision to grant exclusive custody of her child to child's biological grandmother was not conduct inconsistent with her protected status, where evidence showed intervenor had purposefully impeded mother's ability to assume her role as her child's parent, and this custodial arrangement allowed mother to assume her role as her child's mother in future.