Wayne, since I have not seen your father's shop, my recommendations are quite general. I do security consulting as part of my job but I make no claims at knowing it all. Obviously your father and his neighbors can fight or take flight. Flight is cheapest. If they choose to fight it should be as a united group, not a single shop and they should have a battle plan. I suggest NO fake exterior cameras - bad legal precedents. Real, exterior low light cameras are pretty inexpensive now. You can actually buy a 9 camera system with infrared lighting, motion detection, combination DVR and multiplexer, remote viewing (can log in to view the worksite from any Internet PC), cables and monitor for about $2500. Contact the power company about adding some pole lighting to brighten the area (for a deterrent). If county code allows string barbed wire on stantions pointed outward on the top of the fence. Close and lock the gates at COB each day. Meet with the proper law enforcement agencies, if possible include a reporter.
I subscribe to the "broken windows" concept of crime prevention which is basically that if you allow a small problem (i.e., broken windows in abandoned businesses) to go unaddressed, the problems will worsen and eventually become out of control.
It is doubtful that your father or his neighbors can do what is necessary alone. They need to partner with as many levels of government as possible and they will need to reach out to the adjacent neighborhoods to push the problem further back.
If there is a locally owned security company that conducts patrols using armed security officers talk with them too. Might not be as expensive as you think and there are some high tech methods of ensuring that the patrol is actually conducted at random times, not a route.
The suggestion about a tool cage is also very good advise. Failing that, a simple enclosure made of 1/4 inch by 4 inch flat iron for the rolling type tool boxes can be fabricated. Use high quality hinges or pins and American brand hardened padlocks. Most automotive shops with welders can make their own tool locking enclosures. Bars on the shop windows (if local code allows) are a good idea.
Most business firms will make a decision based on economics and the cheapest solution is to relocate. I wish you and your family the best on this. It is not an easy fight. If it is allowed on this forum, you can contact me off line if you like.