How does one accomplish the same task via text message? I'm asking this sincerely. I've often found myself attempting to provide emotional support over a text conversation and it's really difficult not to feel helpless and drained by it.
There's only so much you can write "I understand. I support you. Etc." It starts to make you feel like a broken record. Trying to just listen leads to them asking "are you still there? Are you mad at me?"
Right. A lot of emotional support comes from touch and tone of voice, things you can't transmit via text. In text, your tools are limited to choosing your words and maybe emoticons (if you normally don't use them). The former is more powerful than the latter, because it takes more effort, and what one needs to communicate primarily is proof that you care.
For example, if this person is expressing doubts about their ability to do something they must, maybe you can express to them why you think they are able by describing the positive qualities you've observed in them (you've taken notice because you care about them) that sets them up to achieving it. If you also think they're unable, maybe it's still a good idea to fail to learn from the experience. You can explain how this sets them up for growth. If it's really bad to fail, maybe you can somehow help them in the task. Even if it doesn't ensure success, increasing the chances a little is often great. Presence can also be very powerful, even if you don't do anything besides being there.
Another example, if they express regret over a difficult choice they made and later saw was wrong, you can remind them that it's not fair to judge their decision after seeing the results. After all, their past self couldn't see the future, and made the best decision they could with the information they had available at the time. The best they can do is learn from it and move forward from that point.
Anyway, originality is key. Otherwise, it seems like a generic copy-and-paste response, and that's not effort.
This is a tough one that takes some real work if it happens at all regularly.
My experience with this has taught me that it can be extremely helpful to address this concern with the person asking for support, in person, and not while actively giving support. It might help to trying coming to an understand about the repetition of certain language being intentional, especially if you can communicate in advance what that language means to you. "I'm listening" has worked well for me.
There's only so much you can write "I understand. I support you. Etc." It starts to make you feel like a broken record. Trying to just listen leads to them asking "are you still there? Are you mad at me?"