I'm 99.99% it can be fixed. Take the butt and the shaft to your qualified mechanic and have them take a look. If no one is close by, do your research before sending it out.
Without holding it in our hands, it's hard to say. Even pictures will only tell half the story.
If you like the cue and want it fixed, get it done. Depending on who's doing the work, less than $100 to get it back in playing shape.
Buy two nuts 5/16x18 at the hardware store. Put them on the joint screw but not all the way down. Just eneogh so you can lock them together. Then use the wrench and lightly see if you can turn the joint screw.
For the shaft, buy a shoulder screw where the threads are 3/4" threads showing before the shoulder and screw it into your shaft and see if you can turn it.
Hope this helps