A lot depends on the actual hike. If it's not technical, I feel it can be done with a lot of committment on her part. Since she is new, you will need to guide it. It will be better if there are bailout points along the way.

With a difficult problem, I like to plan things backwards to "What can I do today to train?"

One thing she can start doing today is walking 6 days a week. The distance doesn't have to be long as there is plenty of time to work up. I'd suggest a mile a day no matter what the weather. Set up a plan to increase the distance gradually each week until she is doing about 60 miles a week. Somewhere along the way a light pack can be added and the weight increased gradually.

The second thing is to start accumulating gear. I'm a strong believer in not sharing gear, but you may feel otherwise. Either way. Here is a list I put together. I would suggest getting the sleeping bag and tent first so she can practice camping in the backyard. Once she is comfortable with that, she can go car camping a few times to see how it works out. While car camping she can hike very simple trails with her pack. Even along a road if that's all there is. If she can go out in the rain, that's even better.

Joining a group or even finding someone else to backpack with would be a problem where I live. But by taking things slowly and with proper guidance, I feel a person could get ready in a year.

I wouldn't dump all the preparation plans on her all at once. Just let her know you have a plan to help her along and if she follows it, she will be ready. For now, I'd just tell her to walk a mile a day for a week and see how that goes. If she doesn't have the committment to even do that, the rest probably won't go so well.