To be exactly correct, he sued for defamation four (4) of the signatories of the open letter, because the open letter was the explicit call to action to cancel him. He can only file suit against persons within the jurisdiction of his home court in the UK, the majority of the signatories, as well as the two accusers are not UK persons and cannot be sued in that context.
Whether or not that vindicates him is an exercise to the reader.
I make no claims or judgement either way. I just acknowledge that information asymmetry exists as do jurisdictional limits. It's not possible in this case for him to ever be fully vindicated due to the limits of the legal system, but whether it's enough to vindicate him for you is up to you.
Whether or not that vindicates him is an exercise to the reader.