You should probably post this video.
If you are third generation, why can't you ask your family? They should know your boyfriend and might have knowledge in this field.
You say you put him in for a three day evaluation but they released him early. What were the tests? You mention screams at night, did they check he doesn't have any sleeping disorders? What about medical issues. Maybe his mind is ok, but a vitamin deficiency could cause problems too. You also need to consider he could be messing with you [don't get mad, I'm saying anyone could lie]
Cleanse and protect. I know you probably tried already, or you didn't want to hear that, bit it's your best answer. Cleanse him and the house, then protect him and the house. Repeat. If what you say is true, repeat a lot, like every week for 2 months, then every month. Daily shielding might be a good idea. Figure out what the being is so you understand what it wants and how best to rid yourself of it.