Any success stories?

I'm friends with someone who suffers from delusional disorder. I'm trying to figure out if I should continue to interact with my friend, or am I just making it worse? She and I no longer get together, and no longer talk on the phone. Partly because she wouldn't return my phone calls, and partly because before I realized she was ill we had a lot of arguments and problems related to her paranoia. She seems to forget that we've had a "falling out" and will email me. All the emails are strange, but some are sweet remembrances of times past, and others are about her beliefs of persecution by family, friends and government. Especially now with all the talk in the news about government surveillance it's gotten bad.

How do I react to these emails? I know from reading all the posts that I shouldn't challenge her delusions, while at the same time I shouldn't play into them. Most of her friends have left the picture, and I can't blame them. But as someone who has known this person since we were 15 years old, I'm just not ready to give up. I have a fantasy where we get together at some time in the future and talk about these delusions like they are part of a past crazy time. Unrealistic on my part, I'm learning. Is there anything I can say to her that will help? I've tried suggesting counseling - not good. I've tried listening without challenging. I've tried reasoning - seriously bad! What should I do? Shes' not in therapy. Should I just respond to her emails like everything's normal? I'm willing to change my expectations of things returning to "normal." Is it helpful for people with dd to continue to interact with friends? I'm wondering if I should see a therapist myself to go over this stuff. If anyone has had any success remaining friends and helping in any way, I'd love to hear it. I'm not ready to give up on her.