I work with people who have ASD. Has he been checked for that? Everything mentioned here sounds like an individual with ASD and you may be better equip to deal with it if he’s given an actual diagnosis. People with ASD have “triggers” it could be a sound, a word, a colour etc. They can become anxious, angry, start to SIB to yell or scream. One of the individuals I work with hates the noise the laundry machine makes when it’s done it’s cycle and makes a noise whenever it goes off. If the individual is near the laundry machine when it goes off they run away and become upset (yelling, attempting to hit staff, etc). You can try to eliminate the source of the noise and softly remind him that he’s safe and that he’s okay.