Yeah, the best to do would be to put dowel in, however, there are a couple of quick fixes too that work just as well.
First one uses toothpicks, same like out
Cliplock strap buttons, but it requires more of them. put about 5 tooth picks in the hole, and glue them with white glue or instant glue, then put the neck back on, the screw should hold well.
Second is a very good fix, one I've done a few times. Mix up a batch of epoxy, but first, take the neck screw, and cover it in vaseline (not built up and gooey, just an even coat) Then, take your epoxy, and fill the hole completely. put the screw in, (screw it in like the threads were still there, dont' just push it in) let the epoxy harden, if you put the vaseline on well, the screw should pop and you should be able to unscrew it, don't force it though, the last thing we want is to strip the screw head. If it doesn't pop and unscrew, take a soldering iron, and put it on the head of the screw to heat the screw up (a lighter would work too, but will leave burn marks anywhere the flame touches) Don't make it hot enough to melt solder, but soon you'll start to smell the epoxy again, as soon as you do, get that screwdriver in there and remove the screw. Let the epoxy fully cool. You now have as close to a permanent thread in there as you'll ever have, and you don't have to worry about redrilling for a dowel and then hoping you get it all positioned perfectly again
