There's nothing unethical with this situation as the poster describes it. Is it unethical for you not to tell prospective buyers of your house what other offers you've received? Is it unethical for you not to tell the other side of a legal trial what character, logical, and emotional arguments you intend to use to sway the jurors?
No, some relationships have an inherently adversarial zero-sum component, and maintaining informational asymmetry could only be unethical if the other party will bind him or herself equally to not taking advantage of your sharing it. And speaking realistically, there isn't a snowball's chance in hell a middle manager of a large company with legacy systems would not fire this guy if this information got out and he were told to directly or was generally pressured to keep down department costs.
No, some relationships have an inherently adversarial zero-sum component, and maintaining informational asymmetry could only be unethical if the other party will bind him or herself equally to not taking advantage of your sharing it. And speaking realistically, there isn't a snowball's chance in hell a middle manager of a large company with legacy systems would not fire this guy if this information got out and he were told to directly or was generally pressured to keep down department costs.