So what if it was said or not, none of the tort elements are met for defamation. He has only made generalized statements, attacking the group in general, not any specific parent or child, and moreover, the parents have only garnered publicity and wealth from the Sandy Hook incident, regardless of AJ's statements and the main stream media discounts and ridicules him on a constant basis, which expresses the opinions of their viewers.
In any case, I feel he disingenuously backtracked on the Sandy Hook incident, essentially stating that it was an entirely legitimate tragedy. Did people actually die there, certainly, just all those that were claimed to have (i.e., there is video of several of the children singing at a football game a year or two after the incident, and there is a photo with one of the children as being a victim in another incident that occurred years later in Pakistani, etc.)