Hi again, Rhinestone! So sorry about your brother and that you and dh have been ill. Hope all are better soon.
It does sound as if your friends are on the verge of being co. Do they see their dss' families on holidays? That might mean that their dss and dils have decided to go lc with them, seeing them only on specific occasions. If they accept that, they'll probably be ok. If not, they could find themselves co.
Everyone has the right to show up to a public event. However, if the parents will be upset and a gp is not yet co or has a chance of reconciliation, it's probably better not to, imho. If there's "nothing left to lose,' then why not? Just my thoughts...