"It's just too early for her to make any decisions. I know she does want to thank all of her supporters."
She added that her sister is "very private, that's why I've had to talk".
Schapelle and her family have been under intense media scrutiny since she returned to Australia on Sunday morning and managed to evade the media in the process.
"We were very pleased," Mercedes said, "John, who is a good friend of ours, the security guard, he pretty much organised all of that".
Kyle and Jackie O asked Mercedes whose idea it was for Schapelle to feature a photo of missing toddler William Tyrell on her handbag when she left Bali.
The move upset Tyrell's family who wrote on Facebook, "we are not happy".
"That was Schappelle's idea," Mercedes said on radio this morning.
"All these cameras, she wants something that she cares about, she's compassionate. Why not use this for something that she thinks should have more coverage. Missing children is something that she's compassion about. She really likes Daniel's law, that's something she's always following. I'm really proud of her."
During the interview Mercedes confirmed that Schapelle is still dating her boyfriend John, but said, "I'm not really sure what's going to happen".
She shot down the rumour that Schapelle is considering being the next Bachelorette, saying, "that's not going to happen".
And finally she urged the media to leave Schapelle and the family alone.
"Please go home," she said.
"It's annoying our children, give us some privacy. She's not going to talk to you."
