The child abuse laws may differ in your state but in my state, consensual sexual behavior with any child who is 12 years old is not consensual if the other child is 14 or over. I would say that the older boy could be charged, and depending upon his mental status at the time, convicted. . And depending if it did happen, which needs to be investigated...That is to say, your son may have dissembled for secondary gain.
If it happened, it is a crime, because of your son's age. And if it is alleged to have happened it needs to be investigated. But such an investigation is usually in house. (If the hospital administrator is involved I do not believe they would hush it up if they were smart, because they would know their liability, I believe, and know that concealment makes it waay worse.) Which is to say that maybe lower level employees were negligent and are concealing this from their bosses, and you will get assistance if you advice the highest level.
In my State all of this is law. Not just in residential treatment centers, but in nursing homes, and in prisons, adult facilities too. To the extent that there is a law called PREA, which I think stands for prison rape elimination act. Rapes are rampant in prison.
The institutions used to be indifferent to prison rapes. Until they started getting sued--for a lot of money. The reason the courts pay out so much money is because people in these settings are dependent upon the care and responsibility of the people that work there--it is a custodial situation. The residents are sitting ducks. Especially kids.
What I do believe, like others, is that the facility responded extremely irresponsibly and stupidly, by not returning your phone calls. They as if invited suspicion. Why in the world would you not return a call...if you were not negligent in some way?
I would call directly to the administrator of the facility. The top person. I would speak with nobody else.
I would call for an investigation. In writing. Now.
I would call the ombudsperson who works for the county where the facility is. The number should be posted. That person (there is one in every county) is paid to represent residents in facilities such as this. If you cannot find the County ombudsman there is a state one. You can google your state and ombudsman and you will find phone numbers.
I might call the police, or I might wait.
I would talk to my son and I would demand that the facility pay for a psychologist specialized in sexual trauma in children, to counsel and to talk to your son. The minute they became aware of the possibility of assault the facility needed (by law in my state, to have your son medically examined. They need to do so, now.. Again, this need for an immediate investigation is triggered regardless of proof anything occurs. All that is required is an allegation. That criteria has been met. At least in my state.)
Finally, if your child should have been on suicide (and he was not) this makes the whole thing even worse. But you do not know yet, what is true, as sish and pigless implied. There may have been secondary gain for your son to get you hysterically afraid and anger and pull him.
But it is not your responsibility to investigate and to prove anything. It is the facility's responsibility to disprove it, by investigating thoroughly and ruling out such an event.
Finally, if indeed it was determined that such a crime took place, or perhaps even the likelihood of such an event, your son might quality for benefits under the victim's assistance program. You would apply through the District Attorney's office in the county where the act took place. The benefits would include free psychotherapy for a year at least. The therapists who do this work are very good. Top. Because it pays a great deal.
The reason I might hesitate to get the police involved right away is because, one we do not want to empower your son if he is manipulating and lying (not to say he is). I would also have the rights and welfare of my child front and center. I think I might want to see how the investigation plays out, and how he is affected by it. I would also want him stabilized first before he was put under further pressure.
I would call the hospital administrator and I would put into writing your request for an investigation, what your son alleges happened to him, with whom, and date it and sign it. I would make copies. If it is a chain I would also call the head office.
I would take this very seriously, as you are doing--but I would be cautious and deliberate.
I am sorry this has happened. As if you needed it. Keep posting (I hope) and let us know.