Dear Jack:
You typed that you are tolerant of your brothers but of strangers- how common that is! I think it is because you still think you need your brothers as you felt you needed them as a child, the approval of your bully brother. Maybe you are conflicted with anger toward bullying traits in strangers and your automatic reaction of submission to such. The former born out of health: you value yourself deep inside and have the natural motivation to fight against those who treat you as if you had no value. The former born out of illness: you acting as if you had no value.
In reality, you have value- this is not debatable, scientifically speaking.
anita