Joseph, I was told directly by one of today’s Gedolei Hador who is the son of the Godol Hador of a previous generation that they had a SJS situation in their family and the wife of the Godol Hador continued to have contact with the intermarried person(child) and to have the person over in her home as well.
I am deliberately being vague as you can understand.
We are not living in the same times as when certain gezeiros were initiated by chazal for deterrent purposes.
So before anyone any one makes a judgment call of this nature, it is a good idea to first speak to their Rav or Poseik.