It is important to remember that all students regardless of previous experience, maturity, disposition, or knowledge of the country in which they will be living, experience cultural adjustment to some degree. As parents, you are more likely to hear from your son or daughter during the low periods than during the high periods as they seek your support. Above all, keep in mind, that a period of mild disappointment, homesickness or depression is a normal part of the study abroad experience and one that passes quickly for most students.
A website that has more information on cultural adjustment: What's Up with Culture?