18 months ago social services took my nephew at birth and placed him with us he has been with us ever since social services applied for a permanent order however they just lost in court and we had to return him to his biological mother who had already lost six other children permanently totally heart broken and not sure if I have any rights to the boy I raised as my son

If the court determined he could go home then there isn't anything you can do. That was their determination. But if they are abusive or negligent again then you may have a chance at getting him in the future