Check with your cell service provider.
Yes you can but the charges are higher and some operators don't have an agreement.
Yes
Buy Roaming sim cards.
if he has free roaming no it doesn't (if he even gets signal) Without roaming it depends on the carrier.
That depends on your plan and coverage area. Unless you have a special cell package for the job corps that likely does not matter in terms of roaming.
If you are traveling internationally, you can take your GSM cell phones and avoid expensive international roaming charges by using a prepaid SIM card. Before leaving, call your cell phone carrier and inform them that you'll be traveling internationally and ask them for an unlock code. After unlocking the phone, you will be able to use your unlocked cell phone with any other carrier's SIM card. When you get to your destination, simply buy a prepaid SIM card and insert it into your device. You will be able to use your phone on your vacation without paying outrageous roaming fees.
Activation of the service is easy: Just text "ROAM ON" to 222 (free of charge), and your roaming service is immediately activated. With Sun's roaming service, you can make and receive calls and texts.
NO
In most cases, just dial the US number the way you normally would, although the cell phone's owner may pay very expensive international roaming charges, depending on the terms of their contract.
You'll get hella roaming charges, and if you're phone is on airplane mode, then no.
I'm not 100% sure, but I dont think so.
It is possible to text internationally, however it is very expensive and may require an international phone.
It depends on who your carrier is. Most service providers don't charge for state changing texts because the service is national. Texting someone internationally would be different though
it would be a piece of mass....roaming in the space(universe)