Can anyone on here please help me diagnose the problem with my mom's car?

She told me that the car had white smoke comming out the tailpipe but the car was not running hot. She drove it like that for only 1 day and not the car will not start. Can anyoue help out a fellow car lover? (and plus I would like to see my Mom out and about driving)

It is hard to say without seeing the "smoke" and how much there was. It could have been steam - which is not a good sign if it was a lot of "smoke". That could indicate water getting into the cylinders. If it was not a significant amount, that is normal. Most cars produce a little "white smoke". Not sure what else to tell you.

Will the car crank or is it completely dead?

Check the pipes.

sounds like a head gasket failure. do a compression check.

Check the pcv grommet where it goes to the valve cover. If the grommet breaks, it will suck oil at an intense rate. Also, it will foul the plugs. Change the plugs, replace the grommet and try again. Part number 13271-4m501 from Nissan.