Sorry to hear your wife has fallen badly on the Halfbike. Hope that doesn't deter you from enjoying the full fun potential of it. We always recommend using protective equipment, especially for people just starting out.
It's true that the Halfbike requires practice and determination to master, but that's also part of the fun and the whole experience. Like any new skill one has to learn, the Halfbike can be a challenge in the beginning, but can be quite rewarding once you feel your brain adjusting to the new movements and actually getting better with time. It's all described in our learning curve graph here with some additional learning tips > www.halfbikes.com/manual
You can also check the YouTube channel by one of our ambassadors. He provides thorough and very useful tips on mastering & learning the Halfbike. www.youtube.com/channel/UCBFS-EzzPeNFlyXHrePTG0A/videos
Let me know what troubles you the most and I'll try to provide some additional tips.