This has been going on for over a year?? Yikes! I don’t know what’s going on with your brother, but what you said really worries me.
The first concern is for your safety. He has threatened both you and your sister as well as your boyfriends. What is everyone in the family doing to keep everyone, including your brother, safe?
I hope your parents are taking his threats seriously. I hope they are willing and able to insist that he get the help he needs. You and your sister can certainly help but it is your parents’ job, not yours, to maintain a safe household. If your brother can’t control his behavior, they may have to figure out a way for him to leave. If he threatens any of you, your parents or whoever else is with him should call the police. It may require police intervention to get your brother to cooperate with treatment.
Your brother needs a medical exam. The serious sleep disorder could be causing his behavior or it could be a symptom of something else. There are also a number of medical conditions that can cause irrational thoughts and behavior. I’d also want him screened for illegal drug use.
If he is medically fine and drug free, then it’s time for a mental health evaluation. I’m glad an attempt was made. It’s a shame that he wouldn’t cooperate but that shouldn’t end family insistence that he get help. Did your family sit down with him to let him know how concerned you all are? When a family convenes with love and concern, it is sometimes enough to get someone into treatment.
Another approach is to get everyone else into family therapy — with an invitation to him to be part of it. A family therapist will help you all figure out new ways to respond to your brother that might get him into treatment. In addition, a therapist will know the legal resources and social services that can assist all of you, including your brother.
Bottom line, though, is this. Safety first. It’s often emotionally wrenching for families to call the police or to get a restraining order on someone they love. But, from my point of view, hard feelings are preferable to physical injury to family members and the resultant arrest for assault on someone who isn’t in control of his actions.
I wish you all well.