Any sanctions would have to be agreed upon by the UN security council, Russia and China would block any move against Egypt by any other member nation. The majority of the worlds powers have greater interests in Egypt and the ME than they do in Ethiopia and thus won't have a problem turning a blind eye especially when this is a matter of vital national security to Egypt.
EU and the US are very close allies of Ethiopia and will certainly get involved. I assure you that most world powers do not have any interest in Egypt whatsoever. Egypt might be a weapon buyer from Russia , but that's that. Egypt is devoid of any significant natural resources like petroleum and has no major industries to speak of. On the other hand, the world needs Ethiopia's help fighting militant groups like Al Shabab and Al Qaeda.