From this extract it would seem that the family member may be able to travel alone, as now within the Schengen Area.

The Court of Justice confirms that Directive 2004/38 is applicable to the situation of the McCarthy family. The directive applies to any EU citizen who has exercised his right of freedom of movement by becoming established in a Member State other than the Member State of which he is a national and to his family members.
There is nothing in Directive 2004/38 indicating that the right of entry of family members of the EU citizen who are not nationals of a Member State and the exemption, laid down in the first sub paragraph of Article5(2) of the directive, from the requirement to have a visa are limited to Member States other than the Member State of origin of the EU citizen. Thus, where a family member of an EU citizen who has exercised his right of freedom of movement is in a situation such as that of Ms McCarthy Rodriguez, that family member is not subject to the requirement to obtain a visa or an equivalent requirement in order to be able to enter the territory of that EU citizen’s Member State of origin