Volt meter baloney, shiny objects.....ARRRRRGH
The starter will do something with 11 volts, may not crank, but it would react. If you are concerned, hook a set of jumper cables to it, that will tll you immediately, the car should start. Batteries do go dead, doesn't really mean they are junk.
If you unhook the small lead to the solenoid, and your wife turns the key to start with the clutch in, does it have power to it? We know the starter is good, so my guess is no
So, if not, work towards the key.
If you have power to the clutch switch, step on it and see if you have power out. If you do, follow the wire further on down. If you don't replace the switch