Having yo-yo'ed between two countries six times in the last 13 years, I have some experience in this matter.
This is not a simple question. Relocation from one place to another, anywhere in the world, is a 1st/4th/7th house question: the 7th house being the relocated place. You look to the 9th house ruler as well, and see what it's 'doing' in the chart. In several of my personal charts about these moves, for example, the 9th ruler would be shown in the 4th, indicating (for me) that the 'foreign place' is actually my home. POF will show what, or where, the person values.
As to being able to tell whether a person will come back or not, I don't think this is possible, unless the 'coming back' takes place in a relatively short time.
Free Will plays a huge role in life, so the choice of whether to come back or not, is the person's choice (so to speak). If the querent's significator, or one of the major relocation significators is retrograde, of course, you might have your answer already.