PhD examiner disappeared, what I can do?
In circumstances such as this, you should consult the faculty member or administrator in your department who is responsible for overseeing the thesis examination process for doctoral candidates.

Different departments have different ways of handling such non-responses. In some cases, they may simply say that the examiner has, through non-communication, implicitly accepted the thesis "as is." Other departments may unfortunately insist on having both examiners "sign off" on the final submission before it is accepted. My department, for instance, leans toward the first policy, in that it is the actual supervisor of the student who "accepts" the final submitted version of the thesis.

However, without talking specifically to people in your department, it is impossible to tell you what will happen here.