Cat c12

I have a cat c12 in my ford sterling truck the problem is, truck ran really good Dec 28, its been parked ever since got into truck and tried to start it and it won't crank, the motor will spin but won't run, truck is getting fuel, will try to run with gas rag on filter but just spins and dies, could the pcm go out just like that or could it be something else, any help would be appreciated as of right now clueless, I have had a roadside mechanic look at it but still can't get it to fire and run

 

It will run off ether but as soon as ether burns off motor just turns over same as with gas on a rag, no check engine light comes on when ignition is turned over, checked fuel by the fuel pump, then we drained filter and just turned it over and they filled back up, in a little bit going to check see if injectors are getting power, it just strange it ran fine, and cracked fine all day last week, no check engine lights or nothing, turned truck off been sitting g for a week and now like I said it turns over but won't start, the other strange thing is that the battery's keep dying in it all 3