As long as Mr. Dassey's name remains one of the tags in this thread, I will assume that discussing him is not off topic. You have every right not to participate, if you do not care to do so. I don't recall saying that pointing out his false confession did help Mr. Avery directly. However, before giving a final answer, one might consider Mr. Miskelley's confession in the West Memphis 3 case, which made it in through the back door.
I am very familiar with that case as well (WM3) and I believe Miskelley also gave a false confession. However these cases (Avery and WM3) are very different as in the WM3 case there was no physical evidence linking any of the accused to the crime, and that made it more likely that Miskelley's confession was not genuine as it did not match the known facts of the crime. Dassey's confession also did not match a lot of the known facts, but one cannot just discount the mountain of physical evidence that links Avery to the crime.
There are other problems with comparing the WM3 case to this one, but the point I was making was not that discussing Dassey is off topic, but that I don't see how a valid argument can be made that Avery is innocent because Dassey likely is.