Although, it does look like a hack job, and some wires were cut. That could be the result of someone wanting to remove the unit quickly and not knowing what they are doing.
The monitor shell is made by Bybyte.com. You may be able to contact them for some assistance.
The 9-pin miniDIN plug is a standard cable for either Lilliput or Xenarc monitors, I believe. I am pretty certain I have seen replacement cables available for sale.
The power harness for the radio should be fine for the monitor, but the rest of the equipment should have dedicated power lines run from the battery.
It's a safety issue.