The reason the dependent cannot travel, despite having a valid visa and e-COPR, is that the landing procedure for the primary applicant has not been finalized.
Dependent may travel by using another type of pre-approved visa. i.e. Visitor
Thanks again
He doesn't need to be here for any other reason than "land" so we aren't worried about that
He is doing an internship to finish graduation
So he would just be coming here for 2 weeks to "land" and then go back until the summer
Now we wait but getting the P2 email and submitting our landing and phots is a huge relief thanks to you and others!