writ of habeas corpus

A writ of habeas corpus only applies if someone is in custody unlawfully, so I don't see how it would help here.  The best advice for your husband is to "grin and bear."  They won;t succeed in making him angry if he simply controls his temper.  To avoid going back, that;s what he'll have to learn to do.  Getting into a battle with the Department of Corrections is a bad idea.  They have the power, and they have him in custody.  I don't think filing motions at this point is a good idea.  He can always talk to a lawyer about the mistreatment he endured when he gets out.

Although I do not practice law in the State of California, here are my initial impressions.  The general rule is that although it is possible for an individual to file documents without an attorney, otherwise known as "pro se", it is never a good idea.  Moreover, if your husband is currently being held against his will, or in a situation where his rights may be at risk/violated, I highly suggest that you consult with and/or hire an attorney as soon as possible.  Good luck.