"Mike logged into the company’s GitHub repo with VS Code and utilized the Git Blame tool."

If Mike is an actual lead developer then he should be checking the repo commits regularly, or better still, the project should be setup in such a way that Dave has to submit pull requests for Mike to approve.

Given Mike is also the owner of the business, as well as being technical, then it makes no sense that he didn't have such a basic workflow safeguard in place. Mike sounds like a total amateur.

News at 11: man shoots self in foot and blames gun.