Did/could Bhante Khemakumara install Bhante his email so that he would get notification (otherwise he would be lost, used to messager and co.)
Probably there is no such general e-mail app, which could be set up to work with any e-mail address, installed by default on any Android phone. I think in most cases there is an app for GMail (Google's e-mail service) installed.
Some e-mail providers offer their own Android apps, only working with their own e-mail addresses. There certainly are also general "free" e-mail apps found in the Google PlayStore (examples:
BlueMail ,
Edison Mail - I have never used any) which could be set up to work with any e-mail address to give notifications.
Not sure if possible and proper to install such an app from the Google Playstore.
I assume currently Bhante would simply read his e-mail by logging in through the web-interface at
https://mail.greensta.de , probably not well accessible for mobile devices, and not possible to set up notifications, as far as I am aware.