gary,
thanks to Lp for the diagram.
It looks to me like the meter you have is a copy of a Simpson. It seems to have the same ranges.
Its a pity about your brother, BUT. Is the meter movement in this meter functioning? If so, you may be lucky now you have a circuit.
Switch D is the DC volts and mA range selection; R19,18,17,25 are the volts standards and R16 is the 2.5 volt standard. This is 48 K ohm and when added to the 2000 ohm meter movement resistance gives 50,000 ohm. For a 20,000 ohm per volt sensitivity, this is the correct value for a 2.5 volt range.
switch A is for selecting the ohm range. R1 is for the ohm x 1 range; It is 11.5 ohm but the residual wiring and switch resistance is taken to be about 1 ohm so the total resistance in the ohm x 1 circuit is 12.5 ohm. This is the ohms value at the 50% deflection point on the meter scale. R1 plus R2 plus R3 adds to close to 1250 ohm for the ohm x 100 range.
Switch 2, B1/A1 position is DC/Ohm ranges. position B2/A2 is AC volts. Position B3/A3 is for AC measurements where there is a DC level on the AC signal. The capacitor C1 removes the DC component.
switch AB has the AC voltage range setting resistors.
I'll keep a watch on this thread for you.
Hope you get it all going OK.