Yehudah bar Yeshua is Aramaic for Judah, son of Jesus (also Judas or Jude )
So the film finds that as this says "son of Jesus" this must prove that it was the Jesus in the tomb who married the woman in the tomb they call Mary Magdalene and hence this Judah must be their son. See the DNA test for their prove.
We have heard that Jesus married Mary Magadalene before this but this is the first time we have ever heard of this son. None of the writings over the centuries ever came up with this. In all that Dan Brown wrote this was not suggested. So how can this conclusion be reached.
So what is the story the film suggests? Jesus and Mary marry and have a child and name him Judas - I suppose after the wonderful treasurer who betrayed Jesus and caused his arrest.
To me it is evidence that the people in this tomb are nothing to do with Jesus Christ.