You should never try and hide that fact that you care. My approach would be a text message saying something along the lines of: Hi X. Hope things are going ok

You should never try and hide that fact that you care. My approach would be a text message saying something along the lines of: Hi X. Hope things are going ok. Tell us if we can do anything. Alter for cultural differences, closeness of relationship, situations where things are not going to be ok.