Arthurian connection to PIE word for sibling

When I did a little post about Proto-Indo-European on a forum I
frequent, one of the girls noted an interesting similarity. Could
there be a connection:

"The word "gwelbhus", for "sibling," reminded me of Gwenddydd,
Merlin's sister (sometimes twin) in Arthurian Legend.

...how's that?"

Or is this a misconnection due to the "gwe" as the beginnings?