There is no point in asking a man a question until you have established whether he has any reason to lie to you.
Your source material is the people you know, not those you don't know, but every character is an extension of the author's own personality.
I'm a typical middle child. I'm the mediator. The one that makes everything OK, puts their own needs aside to make sure everybody's happy. It's hard to change your nature, even with years and years of therapy.