It makes sense and explains why Carlo never faced a serious indictment during his remaining years. This isn't the first time I heard this, and I forgot where I read it, but I remember reading from another source that Castellano was AB as early as '67. Carlo was still alive at this point and fairly healthy, he just handed most administration duty to his cousin to avoid heat, with Carlo still relatively healthy, what possible conflict would there be with Neil? If Neil tried anything it would essentially be him going against Carlo, I doubt he wanted that.