This topic somehow made me recall of a certain other topics that pertain that if Bitcoin could be sent by SMS.
Entirely possible. Once you have signed a transaction, it can be sent by any medium you like to anybody you like. If you know someone or some service who has an internet connection and would be willing to broadcast it for you, then you can send it to them via SMS and they can broadcast it.
I thought I read something about sending Bitcoin without Internet quite a while ago. As far as I know there are ways to broadcast transactions and to receive it as well.
The most developed project is
https://txtenna.com/. Basically you buy a small transmitter unit, which connects to other transmitter units in your area to form a local mesh network. When you want to broadcast a transaction, you unit will send it to every other unit in range, each of which will relay it to every other unit within their range, and so on, almost like a mini network of bitcoin nodes. Once it reaches a unit which also has an internet connection, then that unit will broadcast it to the network. You then stay up-to-date with the latest blocks via Blockchain Satellite, again with no internet connection.
You can see the GitHub for this project here:
https://github.com/remyers/txtenna-python