Colombia Question Please Help?

My brother his wife and one child went to Palmira (sp?) Colombia 2 weeks ago, he called every 2 days. I have his other 2 boys here in Ky with me, we have not heard from them in over a week. I know he has trouble getting calls, but when I texted him he would answer in a second, now nothing. What should I do? Or what can I do? His wife is Colombian but I do not know her family name.