Oh, Isabel, I am so sorry.
We, too, had the opportunity to take in our niece many yrs ago and did not do it. We lived in a small apt. and my husband had gone back to grad school. We decided that between our tight schedules, tight budget, and new marriage, not to mention the fact that the reason our niece needed a home was that her mom kicked her out, it would be a bad choice all the way around.
I felt SO guilty!
She ended up resorting to prostitution, but over the yrs, went back to school and got a college degree, married and had a son. (Not necessarily in that order!)
You made the right decision based on your living conditions at that time. What if your nephew had committed suicide while he was living with-you? There are no guarantees.
Still, I hear you and feel for you.
So sad.
Hugs and strength.