You never know what a jury will do. Anytime you go to court, its out of your hands. Decisions will be made by people that don't know you and will never be allowed to see the 'whole story'. If the verdict had been what you expected, it would still not change what happened to you and your son.
In reality, nothing has changed since the crime was committed. You and your son are the good people and he is the bad person - no matter what the jury found. You know what the monster did, and so does he. None of this mess is your or your son's fault.
The other posts about reoffending are right; there is a 0% chance of rehabilitation for this type of offender. Even if they can control their actions, they always have the urge to offend. There is no cure for the 'disease' they have.
The law protects the accused; in the US, the accused has more rights than the victim. Even after conviction and incarceration, the inmate has different rights than free citizens. Its how the system is set up to avoid malicious prosecution. Unfortunately, its so hard for a prosecuting entity to get a conviction because all the ducks have to be in a row, and if one or some are not, the prosecutor can't win. The laws are set up that way so that "better a thousand guilty go free than one innocent be convicted". It feels so unfair when we all know what is right.
But the good news is that you are in control of your life from this point on. You can grieve and heal and use your strengths to make you better than you ever dreamed. Sometimes we need our scars to make us whole. You are no longer a victim; you are a survivor. Stronger than ever, your life from now on is yours. As I said in an earlier post, it doesn't matter what 10 people that don't know you and weren't allowed to know the whole story decided; you are the good people - you win.