Unleash My Sons

My son is 27 and for two weeks now he's been hearing voices of a male and female, but is unable to make out what is being said. They are pretty much always around him inside and out the home. He feels there presence. He sees a dark black presence with a cape kind of clothing and a face of horror. At night when sleeping he sometimes awakes and can't move or speak like he being held down, other times it just hovering over him, things in the room or moved and he hears different types of sounds. He said it's really draining him, that day by day he feels like a different person, He doesn't know what to do or has no idea why this is happening. Also my 23 year old is experiencing the same thing. I myself however don't experience it, but don't know what to do to make it stop. Could someone please help my sons out and give us some insight on what's happening and what we can do to have this attachment removed from them so they can be back to normal, they are really scared and feel like they are loosing there minds. So anyone with any useful information on what's happening please contact me as soon as possible. I know there not crazy, they just for some unknown reason have this attachment. They have been both very depressed and pulling away from everyone just wanting to be alone, also have become very agitated with everything and everyone. They don't sleep at night due to this and barely eat. Again thanks to anyone who has any useful information they can offer me. I'm slowly losing my sons and need to have them released from this.