Lizzy, I'm very sorry to hear about you're friend.
My BF also has lung cancer. She is 41 and was diagnosed 3 years ago at stage 3. She is feeling fantastic after her radiation and 2nd round of chemo 4 months ago. Her health sometimes took such a dive I thought "this is it" and would get very scared and emotional...she's been in and out of the hospital this year and last, but has bounced back and feeling really good.
I hope you're friend will have many more years with you and hope you will get to Disney with her to make more great memories together.