it will only go up. She bought at $4200

How soon can we REALISTICALLY see $4200 again and upwards?
It's funny! I hope your grandmother sold her bitcoins in December at the maximum price, and now she has a lambo.

In fact, you need to draw conclusions yourself and take responsibility.
Yup, I also hope that she hold her bitcoin because if not then it will be just a small profit over the time or either a loss so it is really a good move to just keep having plans and strategies and targets through the years in order to not lose the opportunities because if your grandmother doesn't have a target price for her bitcoins then she is still holding and already lose the chance to get a lot of profits from december 2017.