I mean, he'll never see the success that Futch and Steward had as they're two of the most successful trainers ever in the pre-eminent individual sport of the 20th century who both had careers of 40+ years (Futch's training career was spanned nearly 60 years). The entire basis of your argument was that he wasn't a great fighter so he necessarily has to be a shitty trainer. Neither Futch nor Steward fought professionally, so they'd necessarily have to be frauds in your eyes. You can throw in guys like Angelo Dundee, Ray Arcel, and Cus D'Amato for men with no professional records who were legendary trainers. Bouie Fisher, the guy who built Bernard Hopkins, didn't have a pro career of any note, either. Freddie Roach wasn't much of a pro. Virgil Hunter, the guy who built Andre Ward, didn't have any pro career. All were frauds, I assume.
As for success in his very brief career as a trainer, he has already trained and cornered a world titlist in boxing (Jessie Vargas). He was trained by Jeff Mayweather, so he has a decent lineage. In a sport with a ton of guys where guys with no credentials (who are honestly pretty garbage trainers) get a fair amount of limelight, trying to claim someone like Dewey Cooper is some massive fraud is bizarre. I'm not even someone who will claim that he's a great trainer or anything like that, just that your reasoning is pants-on-head retarded and that your agenda is fucking weird.