Jones could win with this endorsement, but I think it’s more likely that - like Mo Brooks - he is hamstrung by his complete uselessness.
Jones is one of the worst possible candidates. I usually put more faith in Trump's endorsements than others but I don't think he'll win. He was a party-line democrat until a couple years ago and has tons of abuse/fraud/assault allegations that can very easily be used against him. And he's already pretty hated in Georgia, given that he was targeted by Republicans in the state when he was a Democrat.