Sherwood was sacked back in October 2015, after Villa won just once in their first 10 matches in the Premier League.
Garde was appointed to save the Claret and Blues from the drop, but the French boss has not had the desired impact.
Garde has won just two league matches since taking charge at Villa Park, and Cascarino believes things have got worse, rather than better, under the former Lyon manager.
“Remi Garde, as a manager, has had a dreadful time,” Cascarino said. “It’s been worse than it was under Tim. They look like they can’t buy a goal. They have got 22 goals this season, that will take you down. They have not had a striker for a long time that looks like he can get a goals tally in double digits.
“For a team fighting to stay up they have been woeful. They have not dug deep.”
According to The Sun, Garde is set to leave Villa in the coming days, with the club now planning for life in the Championship next season.
Villa are 12 points adrift of safety now, and they appear to be resigned to their fate - with the side putting in some insipid performances of late.
The bookies’ favourite to take over at Villa is Nigel Pearson, who won the Championship with Leicester City back in the 2013/14 campaign.