Perhaps I can't see the wood for the trees....does an elderly EU citizen who is dependent on EU daughter and EU son-in-law have RTR where it is the son-in-law who has worker status and not the daughter? Does this fit extended family member definition for RTR?
Thanks!

EC directive 2004/38 article 2 gives the definition of "family member" to include the spouse or civil partner of a Union citizen and "dependent direct relatives in the ascending line and those of the spouse or partner..."

As long as one of them is a worker, and they are both EU citizens anyway, then for the purposes of R2R it doesn't matter whose parent he is.