From what he has said it is private property. If he were to report it to the state and they sent a archy out and they thought maybe there was a grave the property would be shut down and fenced off. It could be a very nice score for the state but a big loss for the property owners.
I don't see anything that makes me believe it is a grave site. The State has seen more pottery shards than they ever need ,too, but there may be something significant, there, & I would think it needs to be checked . If it did turn out to be a grave site, just that one small area can be fenced & at no real loss to the owners.
That is Swift Creek Complicated stamped and from the look of the pottery, it may have been made during the Weeden Island time period. If I may ask, what county and what state? I have a collection of Woodland artifacts and they are similar to what you are finding.