RSBM.
If you have a source for that I'd love to see it. Because the only thing I have ever seen record of is Chad telling people that Lori is an "empty nester" (i.e. all her children have grown up and left the home), that she has no minor children, and that they as a couple have no children in their care. In other words he doesn't even acknowledge Tylee and JJ's existence. Well, that's not entirely true... there was that one time he told LEO that he last saw JJ over a month ago at apartment #107 - this after he was married to the woman (unbeknownst to LE at the time) who was supposed to be caring for these children. But even here it's apparent that he tried to disassociate JJ and Tylee from Lori and himself rather than taking any kind of responsibility for their whereabouts and well-being, you know, since he was now their stepfather.
The only people I have seen put forth the theory that the children are still alive, hidden away somewhere, are unrelated people projecting their own hopes and emotions into the case. In other words these are unfounded rumors. Unless of course you have some evidence directly from Chad that he's telling people the kids are alive and well somewhere. But even here, as much as I'd like to believe it myself, I wouldn't trust anything he says as he has proven himself a liar and manipulator already. Until he can bring forth the kids alive and well he's got no standing. MOO.