Might be a solid case but if the poor guy’s paying for the suit himself it’s a very bad idea. Avenatti’s quite publicly broke, even got thrown out of his offices in San Diego last year for nonpayment of rent. While that doesn’t necessarily mean he’s literally broke since he’s no doubt sheltered assets somewhere, it means that winning in a suit against him is going to be a sort of hollow victory. I suspect any plaintiff against Avenatti at this point would come up empty-handed even if they won.
Avenatti should have a malpractice insurance policy. Most states require that of lawyers.