I guess I will have to remind you that you are THE LIGHT of our lives. Your sister is dead, and the pain doesn't diminish much with time. Your stepbrothers, despite the caring we tried to exhibit during their upbringing with (their mother and stepfather), have proven to be grave disappointments in multiple ways. Your new love has two siblings, which should be of some comfort to her and her mother and a potential "extended family" for you.
 Yes, they also refer to his half-brothers as “stepbrothers.”