Why Doesn't God DO Something?

Someone who is also chronically ill, and has a problem with God over this illness asked me "Why doesn't God DO something?!". It was over a text message, which makes answering such a question difficult--so I have delayed my answer. 
Really, though, even for me, this is a tough question. The person is angry at God for allowing her to be sick, and to have a disease that will kill her, and after being told for years by others that she would be healed if only she believed enough, and so she is so bitter against God that she honestly doesn't even want to go to Heaven. 
I feel at a loss as to what to say. Nothing said, of course, can turn someone's head. We are not so much like horses with bridles that we can turn other people's heads. 
I guess that, for me, I feel so much better clutching God's hand that it doesn't matter too much if I am sick. I hate being sick, and it will probably kill me, too, someday. I hate the limitations, the cursed-half life, missing out on having children, a career, normal daily activities...but then there is God. Someone to cry out to in the night, Someone to ask questions of, Someone who loves ME all the time, and never, ever leaves me alone. Someone who is so powerfully full of love. 
I guess that the time I spent with anxiety, depression and eating disorders solidified my love for God--or rather, really, the Love that HE had for me. I always doted upon God, leaning on Him as a pre-teen with friend issues, but it wasn't until I spent time praying through every bite of food that entered my mouth that I really began to see the love of God. He never left me alone during one of the worst experiences I had in my life. He was there, walking beside me as I paced in panic attacks, giving me peace as I begged the panic attacks to stop. He was there at night when I was depressed and terrified and didn't want to wake up my mother for assistance. I learned then that God was reliable. I learned then that God was unchanging. I learned then that God was powerful, and could heal you, sometimes through the work of your own effort. 
Then, I had a fiance who broke his hold on God. He challenged every verse , saying it wasn't Hebrew--or it wasn't Greek. My faith wobbled the worst that it ever had, and so I read the entire Bible (I did skip Psalms) as I searched for the one verse that would prove a point to myself. I read harder and faster then than I ever had. I hit Col 1.15-19; and it was the final blow to a hot sword, giving me the last needed weapon for my faith. This was truth, God was truth, nothing was wrong with what I had thought of God--it was all truth. This was the last sword needed for me to take on the next battle: chronic illness stripping me away from me. 
How do I answer someone who hates God for their illness when I love God for being there with me with my illness---with everything I have faced? To another it is so eclectic to tell them that God is with me, and that is generally enough; only on the sickest, worst days do I mutter why can't I be healed too?
Part of life is being molded into the Creation we were supposed to be. We are born wicked, sinful creatures, a glimmer of who and what we should have been. Our bodies are full of genetic mistakes--I've taken Anatomy and Physiology, we really shouldn't age, get sick, or die. I can see how easy it would be to not have aged or died in the Beginning. So we enter this world wrong, and we leave it wrong. Yet hopefully, spiritually, we have nearly met the goal by the end of our lives. 
I wish that God would heal me. I really do. I despise being sick, and there are so many days that, regardless of what works God is handing me during this time, I just don't want to do this any more. I;m tired of hurting, feeling sick, weighing activities and my energy level and my nausea level to see if I can do it. I'm tired of people judging me, not believing me when I say I am so sick at times. I hate the looks in others' eyes when I say I am sick. Those few who do see me when I am bad are so concerned for me that it is a warm blanket of comfort. 
I digress. Answering this question has bugged me now for a week and a half. The only thing I can think of is speaking of the above, the times God didn't leave me, and that the strength He gives me is worth more than gold. Yet if this person isn't saved there probably wouldn't be any sensation of God being there, holding onto one as one struggles against the world and the illnesses of it. 
The other thing I can think of is agreeing the Joni Eareckson Tada, who said that I may not be healed here and now, but I will someday, and that matches the pray and you will receive verse that people sometimes-unhelpfully-throw at you when you are sick.
The other thing I can think of is Paul, of all people. If Paul of all people was not healed it seems to me that sometimes, for often unknown reasons, God says no. I seem to be being given a no, and being pushed into doing things for God that I never would have considered in a million years.
How would you answer the question? How does anyone answer it?