I'm not going to get into the legality of removing a soldier from his civilian job, but I will point out that life must go on back home. Some jobs just can't wait a year and a half.
It sucks both for the soldier and the people the soldier leaves int he lurch.
"The people" voted to leave themselves in the lurch. Voting for a pro-war candidate means that you accept responsibility for paying for massive amounts of medical care, housing, equipment, etc that are always associated with combat. Additionally, it means you accept the damage to the economy and essential services caused by Guardies who leave their day job to go fight in a war. A massive number of folks in emergency services (cops, EMT's, nurses, et al) are in the Guard or Reserves. The country obviously has no problem benefitting from the wider level of experience caused by having Reservists who have been extensively trained by the military. Surely they shouldn't have a problem when the bill comes due.
The solution is not to stab the Reservists in the back. Bad idea, that. I'll leave it to your imagination to fill in the potential consequences of making it policy to stab veterans in the back for convenience's sake. The solution is to accept an ounce of friggin sacrifice that the township knew ahead of time was maybe coming someday and deal with it in a legal, efficient manner.
Thor's suggestion is legal, practical and an excellent idea. No person, especially in an emergency role, should be irreplacable. The chief should have a designated successor who could do the job well enough in case he had a heart attack, got run over by a truck or had to go to war.