Congrats on your ggrandson first and foremost.  Both parent’s have to be carriers in order for your ggrandson to be affected.  If they have other children, the children could be carriers, but being a carrier isn’t a situtation where they would need meds, so you wouldn’t have to have them tested.  It is a very treatable condition and I am sure all will be well.  We will keep you in our prayers.

Robin