He got some kind of drip indication at 24 degrees. Should have been close enough for a start if all else is well. Strange method though.
He has low post numbers on our site and probably is not too familiar with older diesel benz engines.
Try to find a 25 year old diesel volkswagon engine with true low milage. It's even harder with the 617 engines I suspect. Unless properly rebuilt in recent past.
Once he is sure he has active glow plugs he might consider spraying some wd 40 into the centre of the air filter and see if the engine at least runs a little. If not go right to the compression check. It is not advisable to use either or quick start for this test. Apparently it is felt that it can damage the engine.