That tractor and engine setup does not need electric to run, it's a full mechanical system.
It really doesn't matter what anything else is doing, if it cranks it should run.
Yes you'll need to figure out the electrical as it won't charge and it may not have power to the glow plugs which will make it start very hard but it won't keep it from starting and running.
It doesn't sound like a main because the key cranks it, so it sounds as if something else is going on.
As far as it not starting and running:
Did it get run out of fuel? Air in the injection lines
Does it have the wrong fuel in it? Gasoline versus diesel
Is there any smoke when it cranks? White, black, none
Does it have the proper mixture of Antifreeze? If it in an are that has froze
As far as it not starting and running:
Did it get run out of fuel? Air in the injection lines ? Answer, It shouldn't have as I fill it everytime I finish using it, But I will check it anyway to be sure.
Does it have the wrong fuel in it? Gasoline versus diesel Answer, I only place diesel in it
Is there any smoke when it cranks? White, black, none Answer, No smoke
Does it have the proper mixture of Antifreeze? If it in an are that has froze Answer I don't know about the Anti freeze, I assume it does have or did have. But we are not in a freeze area, Coldest it ever gets here is a light frost, So far this yr coldest it has gotten is maybe 48 degrees. I am thinking that she pulled the choke out (her words) with is in fact the engine emergency fuel cut off switch. Thanks to SDT for pointing this out to me. I hope to run over there today and see it it is the emergency fuel cut off