My son uses Spice in HMP - from an angry Dad

Dear Prison Widow.
I have read a few of your articles and would like to contribute to your blog.
My son is addicted to legal highs. He was a respectable young man with a job and lovely girlfriend. Spice turned him in to a violent monster. He hit his Mother; his girlfriend and her father in rages that were uncontrollable.
He has been rushed to A & E twice; contemplated taking his own life and was absorbed in his addiction which in the end the only place for him was the streets because he was too dangerous to have around.
Whilst under the influence of Spice; he committed a serious offence and was rightfully sent to prison. As a family we were relieved and thought that prison would help him to address his addiction. Wrong! He now uses other substances in prison and me and my wife have cut all contact simply because his demands for money were as bad as when he was living on the outside. We are not prepared to enable our son whilst he is serving a prison sentence. Yes I understand that family support and regular contact is important for families and prisoners but.... I am not enabling my son to use drugs whilst he is in prison.
We were advised to set boundaries but have you ever tried doing this with a drug addict? They will lie and jump through hoops to get their hands on money!
It's not good enough and those people who are honestly deluded enough to promote family contact make me sick to the pit of my stomach. Drug addicts should NEVER EVER be using substances whilst serving a prison sentence and the Government need to start cleaning up their prisons pretty quick sharp in my opinion. I am disgusted and outraged that my son is still using drugs whilst in HMP!