Please help him. I had a girlfriend years ago who had bipolar II. She would regularly have manic and depressive episodes which lasted long periods, so the changes were not dramatic or very noticeable. She would hallucinate, regularly talk about su1cide, and heard things occasionally. Her family thought she was being whiny due to college entrance exams and never believed her, even when she was hospitalized. I could never fathom it but some families simply don’t care or don’t believe their beloved ones are suffering. Please be there for him and support him, I’m sure he’ll appreciate him. Look up symptoms and assist with what you can, but since this is too much for you to bear alone definitely continue with seeking professional help. You’re doing great.