Hi Vladimir, your friend find a very special broom!
I hope it's scions are thick enough for grafting, most of the time they're (to) thin which will make it difficult to propagate it by grafting.
If this is the case you can always try to root it as a cutting...

Congratulations as well on this new find Vladimir. Here, we root only the hemlocks, however I like very much the idea of grafting to preserve new witch, then later to return the rooting-only going forward.

Dax