This isn't a newly discovered fundamental particle. This is a new form of behavior observed in ensembles of particles, in this case superfluid helium. This is an exciting new result in condensed matter physics, not particle physics. It's kind of surprising how much the mechanisms of particle physics (gauge fields and all that) carry over to describing the collective behavior of particles that's studied in condensed matter physics.
As to the sibling's comment from Lindsay LeBlanc, I don't believe that at all. While true magnetic monopoles are allowed by our theories, we just haven't seen any real evidence that they exist, and that's a bit strange. Personally, I don't believe they'll ever be observed.
(I used to be a particle physicist, for what that's worth. Take my opinions at face value!)