He was working full time as a strawberry picker in Whakamarama at the time of his disappearance.
Mitchell got a Facebook post up within days to ask if anyone had seen or heard anything.
However, after multiple comments and shares, only one person replied with a possible sighting in Te Puna.
Other than that tip, Mitchell said the family was "absolutely in the dark".
Mitchell described her brother as a "well-loved" and "outgoing guy" who would give the shirt off his back to anyone.
"He is so caring and giving... he is always taking us out for lunch and looking out for the family."
Varley was very much the "outdoorsy type" and loved getting out to scenic sites, she said.
Family from Hastings and Rotorua were arriving today to help with the search, she said.
"All we can do is try," Mitchell said through tears.
"We are just trying to keep it together and stay positive."
Mitchell said no one was sure what he was wearing, but he was known to wear Hunting & Fishing tops and shorts regularly.
He was last seen in his blue Nissan Pulsar, which had also not been found.
The family had spoken with Varley's landlord who confirmed no one had been in or out of the rental to their knowledge since last week.
Inside the flat, no clothes or any belongings were missing, she said.
"We are so stressed out, but we are bonding together as a family like we always do to get him home."
She said they were just hoping "more than anything" that Varley was okay.
A police spokeswoman said a missing person report for Varley had been lodged yesterday, but a formal report was yet to be made.