Well, I see why you wanted a topic-specific community for this; it's a lot to try to answer with a 'simple' answer.

I guess to answer your first question, you're already giving her the best support you can. You've done the hard part, acknowledging the situation and taking the time to try to process it.

The most important thing is communication. Clearly, with both of you dealing with similar yet different issues, the process is different on both sides. The main thing is to keep things as open and honest as possible and work through those harder times.

Sloth and steady does it, giving her the space she needs to cope. My personal suggestion, (clearly not a doctor!) would be to remind her you're there when she needs you, without obligation for a reply. No pressure, just reassurance.

Wishing you all the best!