You can't press charges by citing the constitution. It's a general law. Criminal code and criminal procedure code are the relevant laws that should be cited

Yes there is this article which states forbiddening a threat and if the evidence is legit and fullfils other condition he might face some punishment. But before opening a case please I advise you to talk to local lawyer which might cost you from 100-250BIRR. I hope this helps

I dont think its written on z constituiton but its on criminal law. And ya its possible