One should be suspicious of this material - and of its eccentric author, Karl Felix Wolff (1879-1966). He lacked training and he had bizarre if not racist views about the "Indo-Germans" (as the Indo-Europeans were referred in the nineteenth century before the identification of the Celtic language group as being "IE"). The racism does not automatically discount his research into the Ladin people, but it, together with his lack of training and his unusual methods, is a red flag.
It appears that Wolff claimed to have done a great deal of collecting of oral tradition, justifying his stitching together of his so-called national epic. The evidence suggests that his material may have been terribly "thin" and that there was more stiches than fabric.
This was a common practice in the nineteenth century, being behind MacPherson's famed epic Ossian cycle and even to a certain extent behind Elias Lönnrot's Kalevala. Many nationalist authors felt justified in "filling in" the blanks in the name of creating a national epic - and thereby to foster national identity.
I am not an authority on Wolff or his so-called epic, but from what I have found, it looks terribly suspicious - as folklore. It is extremely interesting as an expression of faux folklore (what is now often called "folkloresque"), a cultural expression in imitation of folklore, intended to fit into a nationalist ambition at a time when these epics attempted to achieve certain goals.