Cassano has revealed plans to hang up his boots in three years.
"I love him and that's why I urge him to think long and hard before leaving football so soon," Fascetti, who bossed the forward at Bari while he was a teenager, told TMW.
"Life outside of the game is so different. Football is enjoyment, problems arrive when you stop playing.
"I think he's just tired of all the commotion after one of his reactions. Everything that he does is amplified 100 times. People exaggerate when evaluating him.
"I don't know if he'll reconsider his plans, but I hope he does."