It is unlikely his rights were violated. He is required to have an initial appearance before a judge on the issue of bail "without unnecessary delay," which the courts have found to be less than 72 hours, depending on whether a weekend is involved or not. It is likely that his charges are far more serious than the other people he was locked up with, since you sustained a serious injury.
Since he has been released, he is not required to have the preliminary hearing until 20 days after his arrest. If he were still in jail, the courts are required to hold them within 10 days.
The reading of the rights is a myth perpetuated by TV. They are really only required to read the rights if the police intend on conducting a custodial interrogation
after the arrest of the suspect.
There is no "right" to see one another. The courts are allowed to impose a no-contact order as a condition of release, particularly in a domestic violence
case. You can ask the court to lift the order, and the judge may do so if he is satisfied that you will not be in any danger, but is not required to. Given the nature of your injuries, the court may decide to keep it in place. If either of you do anything to violate the no-contact order, including having contact via third parties, his release could be revoked and he could be sent back to jail pending the trial
The best thing he can do is to get a lawyer, to continue with alcohol treatment, and to obtain counseling and/or anger management. The fact that he has no record will help him. Usually for a first offense the court will grant probation, although because this case involves a serious injury the prosecution may try to seek some kind of incarceration. The more he can do to demonstrate to the court that he is taking the proper steps to ensure that this will not happen again, the more it will help him to get a probationary sentence