Drug Rehab Texas

My sons father suffers from chemical dependence and I don't want my son around him until he gets help through an substance abuse treatment center. I fear that he will abuse my child or even worse while he is high. Chemical dependence I've heard makes people act violent, is this true? How can I make sure my ex gets help through an substance abuse treatment center and be sure he is actually cured from this horrible fate he has found himself in?

My father is in prison due to his drug and alcohol problems and will be getting out next year if he makes it that long. What can I do to get him into an residential treatment for troubled teens center when he gets out on parole? I don't want him to have a drug and alcohol problems relapse once he is free. If there an residential treatment for troubled teens center that will take him straight from prison?