If this were my truck, I'd buy two or three quarts of Dexron II  ATF.
(which works nicely in PS pumps.)  Fill the reservoir up to the top,
and start the motor. Run the steering wheels left and right all the
way to the stops. Fill reservoir again, this time about two inches
from the top. This will fill the system with fluid.

Look for leaks along the metal lines, between the PS pump and the gear
box. On my van, earlier this year I had to replace the metal lines
from the PS pump to the steering gear box. It was a miserable, oily
job. But it did get done, and now the fluid doesn't leak.

Probably not damaged. But, it sure is miserable trying to steer a PS
system with no fluid. Please suggest that he carry a quart of Dexron
II transmission fluid in the truck from now forward.

My son has a 98 Dodge Dakota, a base model.  Last night the power
steering
failed, due to lost fluid.  Today we were unable to see a leak, maybe
due to
the fact that there was very little fluid left in the reservior.  He
had to
drive about 60 miles after experiencing the loss of fluid.

Will this extended operation cause irreparable damage to the ps pump?
We
plan to fill it up tomorrow and find and repair the leak tomorrow.
Any
suggestions would be appreciated.  Thanks, John