I've been waiting for this reunion for a long time, too, and I seem to recall Rianna mentioning her mother's alive in the first fic she appears in. I forget the name, but it was in GA or Exile. She may have referred to her mother in the present tense in a later fic, too.

Vague, I know. =)

"They say one should not speak unkindly of the dead, so I say, 'nice try'." --Lezard