Four wheel drive is making a grinding noise

So she tried the shift into four wheel drive with the transmission in neutral. It did not engage fully and rolled backwards. Now the truck will not move but just grinds when shifted into gear or does it still move okay but will not shift into four wheel drive?

It sounds like you have a couple issues. One related to the actuator, it is the shift motor on the transfer case. It does what the solid levers used to do. Not real hard to change, you remove the front drive shaft from the T-Case and the yoke, then unbolt and replace the encoder then put the front shaft back in. If it is not locking fully in you could get grinding. The other issue would be with the transfer case control module. It sounds like it may be faulty and not controlling the actuator.
Your best bet would be to have a shop that has a high end scan tool plug into it and see if either piece has error codes. Those will not turn on the normal check engine light but they can still be there. Plus they can watch the output of the system as you select the various modes and can narrow it down quickly. Plus they would be able to hear the grinding and how/if it changed during mode selection and give you a much better idea of the problem.