In fact, no one can help her out of her pain now. Seeing your information will make her miss her daughter more. I want to say that you don't even have to add WeChat. Call if you have time, or visit directly. If you are far away and want to care about her, in fact, I think it is good to write to her as a daughter. Talk about your recent situation (happy things), just like her daughter writing to her. But the premise of doing this is that you can persist for a long time, otherwise the sense of loss will make her more sad.