There was a specific forum thread on Cath Info about them. I can't find it. It's more interesting to ask their priests and those who attend their chapels of what they think of the SSPX. They had Cardinal Brandmüller over in Ireland for confirmations in recent times.
The parents could easily have gone to the SSPX. Most of the time its excuses. They either are not seeing the full picture or just don't want to know. In Ireland, the Institute is well supported by TFP. Another group we should stay clear of. I'm not a fan of Tradition, Family, and Property.
I remember a priest having reservations about me attending the SSPX. I thought him a hypocrite given he says both the Traditional Mass and that invented protestant Novus Ordo.
I would stay well clear of the Institute of Christ the King Sovereign Priest. In ways they are an enemy as are modernists in another guise.
What I can see happening is some who attend Institute of Christ the King Sovereign Priest will eventually move over to likes of the SSPX. The other way around would be tragic.
There are a few TFP supporters attending SSPX in Ireland. I would be wary of this.