Lack of thyroid hormone causes depression, forgetfulness, and sometimes irritability. At extremes it can cause psychosis (high or low). It can also LOOK like ADD because short-term memory is poor.
Brain tumors,and other brain diseases,can cause severe personality changes, including abusive behavior. One example is football players that have Chronic Traumatic Encephalopathy. Also degenerative brain diseases like Huntington's disease can cause erratic, abusive behavior. The medical literature is full of accounts of personality changes in brain tumor patients.
There's no point in reasoning with him if he has organic brain disease. Protecting your daughter and yourself (and him, if you can enlist a family member to help him) should be the priority.
