93' eighty-eight. Wont start or read RPMS

During the Fall/Winter this car was very difficult at times to start. I would have to try and start the car 5-10 time some morning. Additionally sometimes when it would start, it would die within seconds.
When I come to a short stop or even sometimes at a light, the car would die. This would also happen or begin to happen when I would turn the car.
I had to replace the alternator in May.And about two weeks ago, I started the car, put it in reverse and the car moved about 2 tire rotations before it died and has not started since. The starter is turning, so thats fine.
The mechanic who is working on the car, told me that he cannot get any RPMs. He has tried replacing the crankshaft sensor and a module (not sure which module) and he cannot find out what is going on. He now believes the the crankshaft sensor he received was faulty.

Any knowledge or input is appreciated and welcomed.

This is basic diagnostics, does it have spark, fuel pressure, will it start if carb cleaner is sprayed into the intake, has the timing chain let go, is the catylytic convertor blocked, no quick answer here, all these checks must be made. If you mean his scanner won't read cranking rpms, suspect wiring to ign. module or module if the crank sensor is ok.

Find out if it was the ignition control module (ICM) that was replaced.

Make sure you have power going to the ICM. Pink wire (pink/black some years) at the ICM wiring harness should have 12 volts while key is on. Also make sure the ICM mounting bracket has a good ground.

Yeah, the mechanic got back to me saying he cannot get the car to start. Says he cannot get an RPM signal from the ignition module. He said he changed the cranksensor twice, the ignition module four times, and also changed the computer. He seemed genuinely bummed that he couldn't get it to work and said he would give me my money back. He brought up maybe a wire is shorted somewhere. I dont understand. I have the key with the tiny chip on it. How would that shut off, I've read in a few posts about the eighty-eight not starting and that would brought up.

If it cranks it's not the key. The wiring from the crank sensor to the icm should also be checked.