You may have algae in the fuel system. Look at the inline fuel filter and if it has black/grey colored crud in it, then it is probably algae. You can treat algae with Diesel Doctor made by Biobor. Follow the directions on the DD tube and have at least one extra set of fuel filters.

If you're getting good voltage from the alternator (13.2 to 14 volts), then I would look at the starter. Auto Zone and some other auto parts stores will check out the electrical charging/starting system for free - either on the car or bench testing. It really sounds like the starter is bad since cranking speed is slow with another battery connected.

When the engine starts look in the oil filler hole to see if the valve train is getting oil. This will eliminate a potential oil pump problem since the oil pressure gauge is not working.

If your friend plans on driving the car any distance I would suggest a valve adjustment. Look at the belts and tighten a bit if needed or replace, inspect the radiator hoses and coolant level, lights including head/brake/turn, etc., etc.

Good Luck!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.