Meh, he could have driven and self isolated there. We don't know the circumstances, maybe it was better for him to self isolate there?
He seems to have gone to his parents' house to "self-isolate" instead of Staying At (his own) Home... And he can't have stayed inside there very well, seeing as members of the public kept seeing him to report him. Way to be a viral vector, Dom.
I do recall hearing that Dominic's father had caught coronavirus. So was that before or after Dom's visit, eh?