Dyche worked with Austin at Turf Moor for around half a season before the striker was sold to QPR.
The Clarets boss believes the Southampton forward deserves a spot in the England squad and feels his defence will have to be on form to keep Austin quiet on Sunday at St Mary's.
He told the Burnley Express: “Just when he got sold, he’d had a really good pre-season, he was in great shape, there was an obvious partnership beginning to build with Ingsy [Danny Ings].
"He was adding to his all-round game and he’s gone on, through himself and coaching input as well.
“The main thing with Charlie, he’s had a life of not proving people wrong but of adapting to the next challenge and he seems to have done that really well, whatever that challenge is. He seems to continue to score goals and be a competitor.
“He has a real competitive edge and that’s something he probably did learn in the lower leagues, and when he got a chance to build his name in the leagues he’s done it. To come through the injuries he’s had, he’s had some tough injuries, but he’s resilient and he finds a way of getting on with his game and nicking his goals."
On Austin's England chances, Dyche added: “There’s a little pool of strikers you can throw in the mix for England. When I was a kid the pool was massive because of the number of English players playing in the top league.
"Now it’s shrunk down. I think Charlie and Troy (Deeney, of Watford) would be amongst the thought process, that’s for sure."