Yes, IANAL but it seems very much like grounds for an open-and-shut wrongful termination suit, given that they have admitted it up front. They could be taken to the cleaners for this.
This guy's back pay of income, severance, and benefits could really add up, but that's more a factor of him getting paid a lot in the first place than wrongful termination suits being particularly fruitful. I wouldn't really describe their payouts as being "taken to the cleaners".
Bringing a wrongful-termination suit is career-killing, so damages could be as much as his entire expected compensation of his remaining career (including equity grants), x6 for punitive damages.
Clinical depression is a mental disability under California law, and thereby a protected medical condition. The bar that Netflix needs to meet is very, very high. Like, operating deadly machinery endangering others while on ketamine. Short of that, no. His employment contract can specify whatever, but state law trumps contracts here. Netflix's lawyer straight up admitted to firing for a protected medical condition.