MattsBamaGirl,
I can only give you an idea of what I think from my own personal experience. I'm a relative placement of a child that was in foster care.
With our case, the bmom and bdad, first told the SW, that nobody in the family would be willing to take the youngest 2-children, when in fact, the oldest was with gma. The gma spoke with my sister and I the first time the children went into care, (she didn't want the boys, only the daughter) but the bmom was working reunification and with crossing state lines, we would have never even gotten the children before they were returned to bmom. (We were never contacted by anyone in the foster care system about anything.)
We thought all was going well in reunification, until we learned (months later) that the children had been removed again and bdad's family couldn't pass a homestudy and the children would stay in foster care. Bmom said the entire time, that there was no one willing to take the children, because she thought if she said nobody would take them, she'd just get them back.
My sister and I had to sit on the CW to get her to even acknowledge us. We did in fact sue for custody of the boys, but in our cases, neither foster family wanted to adopt, but the CW wanted the youngest one to go with a friend of hers and she didn't care where the oldest went. Bmom finally said (before she left the state never to return for "rehab" again) that my sister and I would be willing to take the boys.
The major thing I see for this case going in your favor, is the fact you've had the child for this length of time. It's difficult to say about what the bfamily is telling, because I know for a fact, the bmom in our case, lied tremendously about everything. I also think I would truly not worry too much if I were you, because this sister, would also have to pass a homestudy and that's another hurdle that could stand in their way. (Not saying she can't, but just saying wait and see if she does.)
I have always felt that if a "SUITABLE" relative can be found in a timely manner, the child should stay with family, but that isn't always the best thing for "every" child. I hope and pray this child stays with you as your forever son. He deserves a wonderful family that truly wants him and I think he's found it in you.
Mom2J.
PS- The boys were in foster care in Alabama and yes, I do know a lot about the system in that state. You can PM me and I'll tell you the county they were in.