Advisor ignoring his Ph.D. student after getting tenure
I'm really sorry to hear about this situation.

School officials can not do anything, and changing my advisor after four years of hard work will result in a complete reboot.

This surprises me. Every university differs, but in general you should bring these sorts of issues to your Associate Chair/Director, etc. of Graduate Studies in your department. If they aren't able to mediate with you and your supervisor, or aren't willing to, in most universities that I'm familiar with you should escalate your complaint. Perhaps you have an Associate Dean of Graduate Studies, or if there is a Faculty of Graduate Studies, there is somebody that you can consult there.
Barring this, you should seek advice from either your graduate students association. There may be informal avenues of support that you can pursue.
Most universities have policies around the change of supervisor, as this happens more commonly than you may think.