There was one thing that really bugged me. His sister got scammed and therefore became bip...

bipolar disorder can be genetic but it can also be caused by environmental factors like a traumatic experience (though the trauma is more often experienced in early childhood than later in life)

As far as I understand, bipolar disorder is a genetic illness but environmental factors can trigger the development of it. Just because you have the genes doesn't mean that you will develop bipolar disorder.