As long as there is a couple of gallons in there, it should be enough. If he didn't bleed the injection pump, it is going to take a while to get the air out. That's why it is important to get all of the air out of the fuel system.

This may seem like a stupid question, but is the fuel shut off pushed in? Just trying to eliminate everything that could cause trouble.

When the hand pump goes soft, it is hitting the relief pressure for the low side of the fuel system. I think this is only 30-40 PSI. 

If you're not getting a good squirt of fuel, there must be air in the system, or something wrong with the injection pump. I'm leaning towards air.