This just makes me angry for you. What a manipulation on his mother's part and I'm sorry, but it is incredibly cowardly and inconsiderate to break up with someone over text.

I have a coworker going through something incredibly similar, and it has dragged her down to the point where her job suffered and she has had to take a leave of absence to focus on her mental health. I know it's difficult, but your well being is far more important.