Can I sue the guardians of my adopted son for discrimination?

,The guardians are my adopted son and adopted daughter, the youngest adopted child is developmentally disabled, and bipolar schizophrenic. They will not let me see him or call him, they verbally and emotionally abuse him, because he called 911 so that he could go to the hospital, they refused to let him go, and took his phone away, I'm on SSI and can't really afford a lawyer. Do you think talking to the National Abuse Hotline will help?