The Tykes boss threatened to pull out of a deal to sign the 31-year-old last week due to the Addicks' inability to sanction the deal.
The London club are under a transfer embargo until their takeover is completed, but Davey has not given up hope of landing the former Burnley frontman.
"It's still there, we're still hopeful we can do that." said Davey.
The Barnsley boss is happy with the business he has done in the transfer market and confirmed that Gray would be his final signing if the deal goes through.
He added: "Andy Gray if and when it comes that will be it."