No, that is not being a 10x engineer; maybe he managed the 10x part relative to his colleagues but nothing about his tale (keeping info to himself, letting hims

No, that is not being a 10x engineer; maybe he managed the 10x part relative to his colleagues but nothing about his tale (keeping info to himself, letting himself become a single point of failure, etc.) says he behaved like an engineering professional. If I had to label it, it would be "rockstar", with all the positives but also negatives it implies.