Seri criticised Dembele for going on strike at Borussia Dortmund to force through his move Barca. He also claimed the stress created by such behaviour contributed to Dembele's early season injury.
But Moussa Sissoko told L'Equipe: "When Seri discusses the attitude to adopt, I wonder if it would be appropriate for him to focus on how he could return to his best.
"His transfer to Barça was aborted and he may have remained on that disappointment. Since then, he seems missing in Nice where he is still under contract. And if I refer to his words given to Mundo Deportivo at the end of August, he himself confessed to having exploded with his leaders, whose office walls he shook after he realized he would not go to Catalonia.
"Now, rather than giving lessons wrongly or rightly, or negatively addressing Ousmane's career, it may be time for him to focus on keeping his club in Ligue 1. I want to remind Seri and other critics that Ousmane Dembélé went from his first professional contract with Rennes, Borussia Dortmund and FC Barcelona in less than two years.
"It's a career plan that I wish for everyone."