Jan tells us Ronaiah was with a little girl during the USC meeting who they called Pookah -- and together, they explained how Lennay's sister couldn't come down to visit, so U'ilani sent them instead. Jan says Ronaiah "made it seem as if he was a member of Lennay's family."
After Jan and Ronaiah took the picture together -- Jan says Ronaiah began to act paranoid ... and told her, "Make sure you don't post this photo online."
Soon after the game, Jan says she was contacted by U'ilani ... who also urged her NOT to post the picture of Ronaiah. She didn't explain why.
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There's more ... Jan tells TMZ Lennay's "sister" continued to reach out to her after the USC game ... and delivered some more bad news -- that little Pookah had been diagnosed with lupus and was dying in a children's hospital in Orange County, CA.
Jan said she wanted to send flowers -- so Lennay's "sister" gave her an address. TMZ has learned the address belongs to a member of the Tuiasosopo family.
Jan also gave us the phone number Lennay's sister would use to contact her -- and we found out the number is registered to a man named Titus Tuiasosopo -- Ronaiah's father.