Try
the_func = preprocessFile "..\function\sortbubble.sqf"
That should work in AddOns, so why not in missions...
preprocessFile seems to have some hostility againts subfolders...
loadFile does not support any kind of comments (/**/, //, comment {}..) so it will give error messages if the function uses some...
If this works btw, I'm not to 'blame'
I was told about this 'trick' a while ago...