Viber offers free calls and messages to Android users. It is not just a a messaging platform, but also for sending photos, videos, and also doodle you own drawings to send for loved ones especially abroad. It is easy and fast to use compared to other messaging applications. Although Facebook is also available, I find Viber easier to use if you want to message or call somebody.
My mother is already a senior. She is not that a techie person (although she knows how to use Facebook), but she is happy to use Viber in connecting to my other siblings in different parts of the world. She was once did a doodle “a simple colorful flower” and sent it to my brother. Parents accross the globe have many choices now to connect with their children.