Need advice for my friends help me?

Ok so my bestfriend has been diagnosed with depression and I also know she has been bulimic too. I'm scared that I might say or do something bad that might trigger any one of these things. I know she's talkimg to someone about it. But I just get really scared for her. Also I our other friend has had trouble with the same eating disorder earlier in the year and I'm afraid when she finds out she might start again. I just need advice?
Need advice for my friends help me?
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