Possiblly but no one can tell. So far we can't diagnose it in living people even if they just did a study finding a way how it may be possible. But CTE alone is rarely the reason it may be in some cases but not in all. Some people who have CTE have no symptoms at least for a very long time and some people who have obvious brain damage are still not violent. Each case is different and often it's both the person + the illness.
It wouldn't be super shocking if Mike Tyson ahd CTE but he has also been beating people up since he was 10 or so long before he started boxing and he has had other mental issues as well since his early amateur days. It's easy to take CTe as the explanation for everything involving contact sports but it's probably wrong the media has been very sensationlistic and one sided on that matter and even experts have a hard time exactly explaining it.
Floyd lives a much cleaner live than his dad and his uncle and has better defence and skills but from his family Jeff seems to be the only one who seems to have no symptoms years after retiring. And hes the youngest of the bunch so who knows if he is completely fine in 10 years.